Store Large Trash Bags in Trunk

Keep a couple of big plastic trash bags in your car - trunk, tool box, or gear box - they will help keep the grease and grime off your clothes when you need to change a tire, attach or detach a trailer to the hitch, or add oil/radiator fluid under the hood. You can either just lay the bag on top of whatever grimy thing you need to move (tire?) or cut/tear a hole in the bottom and edges for neck/arms holes and put it on like a poncho to protect your clothes while doing whatever.