Cleaning electronic circuitry?

A year ago my van was contaminated with some kind of super allergen. I'm not sure if it was ultra fine fiberglass or what. But it had me using a month's worth of allergy meds each night that I spent in the van.

I cleaned the van itself out thoroughly, but I have a bunch of items that were in the van that I haven't cleaned.

And the ones that I don't know how to clean are the electronic items with internal fans. I can't have those fans blowing allergens all around my van. Inverters, giant battery charger, etcetera.

If I open up their cases, is it ok to wipe everything down with a damp paper towel? Will I destroy stuff?

If water is unacceptable, is there something else I can do so that the contaminants will stick to the paper towel? I don't want to just dry dust them, because then the stuff will go up in the air.

Would one of those high-powered vacuums you put quarters in at the gas station be a better choice?

Of course these are the things that are more expensive than I want to spend to replace :-).

Thanks very much folks, as always!