Hmmmm.....

I dunno. When I get caught in the rain, which does happen (think
decking a house when a big storm is coming) and cannot stop, our tools
get soaked. Ditto when we go to a job and get caught in an unexpected
frog strangler while sitting in traffic (no doubt caused by rain).

We use WD40 on the nails, not on the tools. Try this: spray WD40 on a
piece of metal, and let it dry. It leaves a film behind. This film
attracts dirt, lint, etc. and makes it into gum on moving surfaces. I
sure wouldn't recommend using it on the tools, inside or out. My tool
repair guy can tell in a minute when the armatures or brushes are
gummed up that someone has been using WD40. That is why my favorite
gunsmith told me to quit using it on my shotguns.

Acetone, etc., will dissolve or etch most plastics. I ruined some of
my drill and saw cases as I was industriously cleaning off tar from the
cases and I noticed the plastic became gummy. Can you imagine what
would happen to the varnish on your motor windings if you did this?

As far as your nail gun goes, forget it. No harm, no foul. How much
water do you drain out of your compressor tank every day? We are
usually in for a few ounces, depending on the season. The point is
this: is you are using a compressor to power your nailers and sanders
and do not have a drying system of filters in place, they are already
exposed to a lot of moisture. If you didn't have a funnel to channel
the water into the housing, you should be fine. Many mornings in the
south where we have extreme temp changes and high humidity you can
actually see the condensation coming out of the exhaust port of the gun
on the high usage guns like roofing nailers and staplers.

So what to do when they get wet? We dry everything off as quickly and
completely as possible. If we have the compressor on site, we blow out
the tools till dry, have some coffee and get back to work. Ideally,
we dry with a cloth, blow them out, and then let them sit overnight
before using.

Never lost one tool to rain as you described... lost plenty to rust,
though.

Robert