Unwelcome Friends

Hello All - this is my first post - good to meet you all!

I have now been caravanning for 5 years.  At the beginning of last season I noticed some what I think are dust mites in the under seat cabinets and other nooks within the van. This suprised me a bit as we keep the van very clean. I have tried a number of off the shelf products such as powders and sprays to see them off without any success, so I trauled the net and found a wedsite which recommends smoke fumers. I Phoned them up and spoke to a very friendly and informative chap who said that this is a common issue in caravans as they are left to stand for long periods of time and can contain damp air which encourages the mites.  I did end up buying a couple of smoke fumer bombs bit am a bit apprehensive in using them as i don't want to contaminate the van with smoke smells or cause any damage to the van. 

Before I drop the bombs so to speak has anyone got any tips or suffered the same problem??