Here's a few practices I follow that support trophy longevity, and might reduce the need for periodic cleaning:
1. Minimize exposure to tobacco smoke.
2. Minimize exposure to kitchen smoke, grease laden air, etc.
3. Try to minimize exposure to outside air during those times of the year when there is more dust or pollen laden air.
4. Use a UV black light type electric bug zapper in every room with trophies (or more in large rooms).
You don't realize how many bugs you have until using one! They do attract and kill dermestid beetles and other harmful species. I suspect they are most effective when the room is dark (except for the UV lamps on the zapper), and I have them plugged in 24/7. They can be unplugged and stowed away whenever you need to "pretty up" the place.
5. When trophies are starting to accumulate dust, I remove the mount from the room and blow it off with compressed air. Use one soft and long bristled brush for horns and antlers. I keep a separate soft and long bristled brush reserved only for the hair on mounts and use it very lightly if at all and both in conjunction with the compressed air. Be sure that the pressure on your air source is reduced so that you don't damage the mount. I use a portable compressor and adjust the regulator so that pressure is fairly low. My compressor is the oil-free type, and I would be reluctant to use an oil-lubricated type compressor. The computer keyboard type compressed air duster might work well as long as you have the ability to reduce the pressure. A hand-held hair dryer might work well if it has a setting for no heat.
6. When trophy is clean, I spray with "Spectracide BUG STOP". It is water based, clear, and leaves no residue and I expect it helps reduce if not eliminate bug infestation. I know a world-class taxidermist in Libby, Montana that uses this on every mount before it leaves their shop. I figure if they use in on museum-quality full mounts like big cats, sheep, ibex, etc. it sure can't hurt! Apply particularly well around toes, hooves, base of horns, tucked or folded areas, etc. where bug larvae seem to favor.
7. After steps 5., and 6., there might be dust remaining on glass eyes. I use a dampened Q-tip to clean the glass. If residue is stubborn (it might be residue that the taxidermist didn't fully clean), Dampen the Q-tip very lightly in acetone, or rubbing alcohol.
