Diffuser or essential oil on cotton wool - want eucalyptus or peppermint

[Katyfour]

I have never had a diffuser or used an essential oils so I am pretty clueless as to how it all works. Advice for the following situation would be appreciated…

Anyway - the problem is that DS’s university room has been damp due to being ground floor and tiny with an en-suite tiny shower room etc. We solved the damp/mould issue with an expensive dehumidifier in his room. This works really well.

Unfortunately, DS is clearly not the only one with this issue - the whole building is pretty crappy and overcrowded and some poor students have been temporarily removed because of water problems. Kids in the adjacent rooms inside his “flat” have mould and silverfish. Today, one solitary silverfish made its way into DS’s room so he caught it and put it outside.

Given that his room is dehumidified and kept very clean, there is not a lot I can think of other than to introduce a smell that the silverfish won’t like, eucalyptus/peppermint. Has anyone used a diffuser in such a small enclosed space or should he just buy a bottle of essential oils and stick it on cotton wool in a glass jar or something? I want to discourage the silverfish without DS being overpowered by scent. Any advice appreciated.

I had success in my damp bathroom by spraying household flea spray around the floor edges. Also stopped slugs and woodlice.

Apart from the initial chemical smell when you first spray it, it's odourless.

It has to be sprayed on the skirting/carpet/flooring - it won't work just sprayed around the room as an air freshener!

Thanks - will look into the flea spray also. Part of my thinking with essential oils was that his room/en-suite is very small and whatever I do, I’m thinking it’ll permeate everything including where his bed is. I know that this building has had silverfish before as well and really do think the main source is someone else’s room.

https://www.aaaai.org/allergist-resources/ask-the-expert/answers/old-ask-the-experts/oil-diffusers-asthma

When I reported silverfish at work, they dealt with it with orange scented cleaner. Apparently silverfish are repelled by orange.

I don't know how real this is but there is a certain logic in cleaning the area the silverfish were found in with scented cleaning spray, rather than trying to sustain the air of the whole room smelling to the extent that might bother a newly arriving insect. Concentrate the smell on the skirting boards, backs of cupboards etc rather than trying to fill the air.