Treating Mouldy Objects - Completed - October 19, 2012

October 19, 2012

Immediately after carefully cleaning and rinsing, the objects treated were hung up outside to dry in the sun for the rest of the day (from 10:30 Am until 3:30 Pm).  Once again, we moved them to follow the direct sunlight since there were shade trees nearby.  When they were brought inside all except one felt dry to the touch.  We did put them out in the sun the next day as well to complete the drying process.  In all cases they were dry to the touch including in all the out of the way places we checked (around folds and peaks on the inside).    Although all visible signs of mould no longer appear we will continue to check them on a regular basis (at least monthly) to ensure there is no additional mould growth.  The black leather gloves continued to have a musty smell which was likely just absorbed due to proximity with the other objects.

The silk insert inside one of the objects was left to dry inside and was dry to the touch by the end of the day. Below is a photograph of the insert showing it removed for cleaning.  The silk is stitched onto a paper backing.  The paper appears to be from a newspaper.

Kings Canadian Hussar's ceremonial hat silk insert 

The objects were all wrapped in acid free paper, stored in banker's boxes, and put away in the museum storage.  A regular check will determine if we have removed the problematic mould infestation.  After several months without evidence of mould growth it would be acceptable to put these objects in with others as part of an exhibit.

Conservation Tip: There are several methods that can be used to remove or reduce the musty odours found on leathers, textiles, and papers .  None of which are guaranteed but might be worth the time, cost and effort.  The best and lowest cost alternative is to place the object in direct sunlight preferably with a breeze.  The sun's ultraviolet light actually will help to break down what is causing the smell.   Keep in mind that some materials will fade with too much sunlight so be cautious and try only a few hours in the sun at first.  Consult a conservator if you are not sure.  Something else you can try which may just reduce odors without having a major effect on what causes them (another lower cost alternative) is storing the objects for a longer period of time in an enclosed container with known odour absorbing materials such as baking soda, charcoal briquettes, or kitty litter.  The objects must not directly contact the odour absorbing materials so put them in an open container inside a larger container that can be closed.  Open it up from time to time (perhaps, weekly?) take the object out and see if the smell is reduced.  It could take several months and is not guaranteed.

Treating Mouldy Objects - Cleaning - October 18, 2012

October 18, 2012

Carefully cleaning the objects to remove any additional mould spores after hanging outside in the sun involves using a soap such as Orvus (similar to Woolite) mixed with distilled water to wash the objects and then rinsing at least twice with distilled water alone.  Washing and rinsing should remove the rest of the mould spores that could be lurking in the materials of the objects.  Damp wiping with a natural sponge dipped in the soapy solution and squeezed to remove most of the moisture will ensure the object is not overly wet.  Do the same when rinsing but use different sponges: a soap sponge and a rinse sponge.  I was very careful with the one object that had several different coloured materials on the inside by using a separate, smaller sponge for each colour.  Testing for colour fastness showed some removal of the colour when rubbed aggressively in non-obvious location with a Q-tip soaked in distilled water.  Being very gentle with the sponge and using different sponges for each colour showed no colour removal.

One of the hats treated has an inside silk insert that was cleaned and rinsed by dabbing with a damp cotton ball.  Since silk is very fragile a wiping motion may have been harmful to the material.  In this case the silk is sown onto a page from a newspaper so I avoided getting it wet.  Excess moisture has the potential to stain the paper.

The first photograph below shows the damp wiping and rinsing in progress.  You can see some of the white mould concentrations on the hat that were removed in this process.  The second photograph below shows the dabbing of the silk insert.

Damp wiping off mould spores with natural sponge

Dabbing silk insert with a cotton ball

Conservation Tips: 1) It is best to immediately hang up the objects again in the sun to dry them out as soon as possible.  Since moisture can reactivate dormant mould spores it is best to thoroughly dry them out right away.  2) Soaps such as Orvus are used because they are more pure than regular soap meaning they are less likely to react negatively with the materials you are washing.  3) Test for colour fastness before washing.  4) In this case (hats) damp wipe instead of immersing them fully in the soapy solution.  There are some cases where a full immersion is warranted.  5) Use natural sponges because they are less likely to have impurities that might affect the materials you are washing.  6) Always wear gloves and a mask plus clean all the tools, containers, and brushes with bleach right after you are done.   The gloves and sponges were thrown away.

Treating Mouldy Objects - Brushing - October 17, 2012

October 17, 2012

Sadly, two of the hats were in very bad shape with a lot of mould visible.  After careful consideration, advice, and discussion it was decided to deaccession them and concentrate on saving the rest of the objects.  These were from the second world war and would have been very difficult to clean.  Some of the reasons why they were removed is: 

1) there are already examples of these within the museum's collection,
2) it is especially difficult to remove large concentrations of mould without damage to the object,
3) the mould has already caused damage,
4) fur on the hat at the bottom is difficult to clean.  

Below is a photograph of these showing their complex nature and the heavy concentration of mould.

Hats deaccessioned (thrown away) due to mould damage

The objects to be treated consist of the following:

1. Kentville Police Chief's hat circa 1950-1960's
2. Kings Canadian Hussars dress cap circa 1900
3. Junior Officer's service cap circa 1972
4. Kings Canadian Hussars wool service cap 1904 - 1939
5. Royal Canadian Navy sailor's cap 1941 -1945
6. Swagger Stick 1950
7. Black leather gloves circa 1920's   

The first step in treating mouldy objects is to put them into direct sunlight preferrably on a windy day.  The sunlight will help to kill the mould spores while the wind will help to dislodge and carry away the loose mould spores.  The second step is to brush the objects with a small paint brush that has medium soft bristles to help dislodge the mould spores.  Mould spores naturally occur in our environment and are normally all around us so all we are doing is removing concentrations of them on these objects.  It is the concentration of it that cause harm to the objects especially fragile textiles.  In the photograph below this hat and the long leather gloves were the only objects that had visible concentrations of mould spores but we treated all of the objects stored together with them.

Conservation Tips: 1) Do not put silk objects or any part of an object that is silk into direct sunlight.  Sunlight and many other sources of light has a cumulative effect on silk and will accelerate its breakdown over time. 2) As shown in the photograph below wear a mask, gloves (latex or rubber), and do not put objects anywhere near air vents or open windows into a building.  3) Clean all objects in any group stored together where one or more show evidence of mould spores.

All the objects were carefully hung up on a line in sunlight for the whole time that the museum was open and were brushed a second time later in the day.  The line with objects had to be moved along to follow the sun due to shade produced by trees.  Here is a photograph of the objects being hung up with clothes pins.

Treating Mouldy Objects - Planning - October 17, 2012

October 17, 2012

Several objects stored in the Kings County Museum started showing evidence of mould growth.  This was discovered by the curator and immediately dealt with.  The curator inspects objects at least twice every year watching for possible mould growth in order to catch it and deal with it before it spreads.  This is an ongoing issue in many museums and requires extra diligence.  All objects must be quarantined when they are donated to the museum for a period of time usually one or two months.  They are examined regularly and only enter the permanent collection when they show no evidence of mould or insects.  In Nova Scotia (as in United Kingdom) where the average annual relative humidity (RH) is over 80% mould growth can happen at any time.  General collections of objects are best stored at 65% RH.

I put together a list of steps to take in terms of cleaning up this mould outbreak.  The steps are based on a combination of advice from the Senior Conservator at Nova Scotia Museum, internet research, and my studies at the university.  The objects were bagged in plastic and stored in a freezer then removed and kept in room temperature still bagged for at least 24 hours beforehand.  The following steps were discussed and approved by the curator before proceeding:

1. hang up the objects on a line outside in direct sunlight preferably with a bit of wind for 6 to 8 hours - make sure that they are not hung up near intakes for air conditioning or open windows into the building
2. brush off the objects with a soft, small paint brush first one direction and then the other - repeat this step after 2 or 3 hours - when done, brush must be soaked in bleach and water solution for at least 20 minutes, rinsed and dried OR thrown away
3. mix Orvus soap (discussed in previous post) with distilled water in a small bowl using only one teaspoon or less of soap, thoroughly mix it
4. using a natural sponge lightly damp wipe the object with the Orvus solution first one direction and then the other - sponge must be soaked in bleach and water solution for at least 20 minutes and dried when done OR thrown away
5. using a natural sponge lightly damp wipe the object with distilled water first one direction and then the other
6. repeat above step
7. hang up the damp objects on a line outside in the sun for several hours until thoroughly dry (again, windy would be best

Note: latex gloves and a face mask were used for all steps where mould spores may be present. 

The objects in question were a collection of military hats primarily from World War II but of particular interest is one from the Boer War which is over 100 years old.  Below is a photograph of all of the objects.  Later photographs will show them in more detail.