DO NOT USE PETROLIUM ON THE RUBBER SEALS!
Tthe reason for this is that the oil residue will not go away and it could also make the rubber deform, swell or deteriorate quicker than normal.
Use dish-soap or glass-cleaner. Most will not harm the paint. The glass-cleaner or soapy water can be sprayed on and make the rubber slick so it can be installed easier than dry. After the window is in, the cleaner or soapy water will dry and let the window seal properly.
