I recently bought a used HP 4L because I think the old HP lasers are great for the amount of printing I do, and I've found them to be fairly bullet-proof. Recently I noticed dark strip down one side of the pages I was printing, so I decided to clean all the wheels - thinking this was the problem. When I did so, I turned the printer upside down , and after that there were grey strips and splotches all over the paper. I pulled the toner cartridge out and could see that there appeared to be toner ink all over the drum. I wiped the drum clean with tissue paper, but the problem persists, and every time I look at the drum, it has excess toner on it. I've been careful to keep the cartridge upright since turning the printer upside down to clean it . Have I wrecked the toner cartridge or can this be fixed without replacing it? Any suggestions?