First, prevention. If you're leaving a car at home, park it in the garage or pull a car cover or tarp over it, this way even if your car gets hit with eggs you can just wash the cover or the tarp!
The quickest way to deter pranks is to make it look like someone's home. Leave the outside lights on, as well as a few inside lights. Leave the T.V. on for the night. The appearance of people keeps pranksters at bay!
Now, what to do if you are a target. toilet paper, don't wait to get it down. If it gets wet it will be even more of a mess.
A broom is a great tool for extending your reach and grabbing the toilet paper.
If the toilet paper is already wet, use more water. Toilet paper breaks down in water so dousing it extensively will remove it from trees and structures so that you can deal with it on the ground.
Eggs corrode paint and cause a lot of damage so act fast, hose, don't wipe off of your house or car, the shells could scratch the paint. Once you've removed as much as you can, clean with some warm soapy water; and then spray it down again!
Shaving cream looks like a bigger mess than it is, it's essentially foam soap, so all you need to do is wet it. Now the trick may be to hit it with warm water first to help dissolve the soap. Then follow it up with a hose for any residual.
Quick clean-ups for halloween pranks. I'm Mrs. Fixit and it's just that simple.