The lowly plastic bag tip The lowly, common plastic grocery bag 
Water Dribbles
Maybe it's just me but I never like it after I wash a car and then for the next few hours water dribbles out of the side mirror housings if you don't have a way to blow the water out.
Water dribbling out of side mirror housing 
Compressed Air
Of course, one quick fix is to use compressed air to blow any remaining water off the car and out of all the nooks and crannies including the side mirror housings. If you don't have an air compressor, here's the handiest little tool you can add to your car detailing arsenal of tools called the SideKick by Metro-Vac.
Blowing rinse water out of side mirror housing using the SideKick 
If you don't have access to compressed air, here's a tip to help keep water out of the inside of the side mirror housing.
Side Mirror and Side Mirror Housing 
The lowly plastic bag tip
Chances are good you have a plastic bag or two from recent purchases at almost any type of store. Simply take two clean bags and place them over the mirrors and then pull the two plastic straps tight and tie them together.
It's quick, simple and an easy way to keep water out of the housing while you're washing the car. Because side mirrors are small you can use any spray detailer to remove any road grime of the housing before doing any detailing work to the outside of the car and use a glass cleaner on the mirror.
Metro Blaster SideKick
Of course, the Metro-Vac SideKick is one of the handiest detailing tools to have in your detailing arsenal for not only blowing water out of the side mirror housings but from all the other nooks and crannies, body seems, emblems, door handles, sun roof gaskets, louvers, headlight housings/trim, wheels, antenna fixtures, door jambs, trunk jambs, hood jambs and throughout the entire engine compartment to remove loose debris as well as any water that has pooled.
On Autogeek.net Metro Blaster SideKick 
Linear Mode
