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The threat from above

By conservators Ellie Rowley-Conwy and Rebecca Hayton

It’s easy to think that pest infestations only happen in dilapidated buildings or the result of poor hygiene and bad housekeeping, but of course it’s never that simple. Even the most sanitary buildings can be struck down with unwanted creepy-crawlies and museums are no different. Once established, an infestation can be very hard to eradicate. But never fear, there are plenty of remedies and some helpful hints and tips that might be useful in your home.

We are going to share with you our years of knowledge and experience, combined with the most up-to-date research that we have at our disposal here at the Royal Armouries, to help you control any outbreaks. Specifically, we are focussing on moths and the potential damage they can cause.

Here in the museum we use traps to monitor the galleries and storage areas. We check these on a monthly basis so we can keep an eye on numbers and track any increases or decreases. Of course, this is  a bit extreme for the home but there are tell-tale signs you can look out for, such as small holes appearing in your favourite woollen jumper or moths fluttering around your lights.

Moths can enter your home in many ways, through openings big or small. Bird’s nests in particular are a common habitat for them so if there are any close to entry routes into your house then this could be a possible cause. Of course not all moths are a problem in the home or museum, the ones you should look out for are the webbing clothes moth, case-bearing clothes moth, brown house moth and white-shouldered house moth.

From left to right: Case-bearing clothes moth, Webbing clothes moth, Brown house moth and White-shouldered house moth

If you find any of these moths there are a number of options available to you, ranging from the cheap easy fixes to bringing out the big guns (not literally even though we are the Royal Armouries!).

Moths are attracted to dark, warm and undisturbed places, living on natural fibres and dust. Knowing the conditions that moths flourish in, gives you a starting point for tackling them. The most simple and effective method is to disturb areas in the house you use less frequently, cleaning away those dust bunnies in long forgotten corners, under the sofa and in the wardrobe.

Speaking of which, if you’re insisting on keeping that old bit of carpet because ‘it might come in useful in the future’, just make sure you vacuum it every now and again. It’s also a good idea to get unused chimneys swept semi-regularly as this is another classic port of entry for unwanted guests (not you Santa!).

Another method available for the treatment of moth infestations is the application of chemical treatments and insecticides, but don’t go rushing to your local hardware store just yet. The use of insecticides is (understandably) heavily regulated and you don’t want to be spraying all sorts of dubious chemicals around your home. Here at the museum we favour a water-based insecticide spray known as ‘Constrain’ by Historyonics. This has a neutral pH and doesn’t damage materials, though it’s always a good idea to do a test first. If you do decide to use this method at home make sure you follow all the safety instructions and keep the treated area isolated from people and animals for 48 hours. This can be highly effective, especially when used in conjunction with regular cleaning of affected areas.

Elephant armour mounted on a model elephant in the oriental gallery being cleaned by a conservator on a yellow ladder being held by an assistant

An example of the extreme housekeeping we have to do at the Royal Armouries, hopefully you don’t have anything on this scale at home.

Obviously, a museum is on a different scale to a domestic home, and can therefore require more extreme measures that are available to the public.

Here at the Royal Armouries we always try to keep up with the latest research and technology which has led us to experiment with a newly commercially available treatment called ‘Exosex CLTab’, an environmentally friendly, pheromone based product. These are tablets placed strategically around the museum in locations classed as high risk. This treatment aims to disrupt the reproductive cycle of the moths, thereby significantly reducing the population. So far we are experiencing promising results but it’s still early days.

Clear plastic mount holding a white tablet

One of the tablets for the Exosex CLTab treatment.

These methods all deal with an infestation once it has occurred, but museum collections need to be protected and preserved for future generations so we need to take extra precautions and prevent infestation occurring in first place. To meet this challenge we have developed an active quarantine procedure for all objects entering our buildings.

We inspect objects on arrival and freeze any containing organic materials down to -30°c. To prevent any damage occurring during the freezing process, we wrap objects with a layer of acid free tissue and seal them in polythene to avoid fluctuations in humidity. Whilst this is generally used as a preventive measure it is also effective for treating infested objects. Heat treatments can be used in a similar way, though this requires specialist equipment to deal with the humidity problem. We use a combination of all these methods, what we in the industry call ‘Integrated Pest Management’.

Obviously, not all of these techniques are practical or even possible to employ in your own home, but hopefully this has introduced you to some of the options out there. Remember, the first rule of combat is to ‘know your enemy’ and know that you are not alone in fighting this battle.

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