Toner cartridge(s) with damaged photosensitive drum(s): which solutions?

I have eight monochrome laser printers, each with a genuine cartridge for 25K pages. Long storage without use caused the toner to localy damage the surface of the photovoltaic drum. The prints are imperfect, with toner depositing in horizontal lines each time the photoconductor drum rotates. There are also lines where the ink does not deposit or fix properly. On some machines, the print quality remains acceptable for printing music scores, but I would however appreciate if it was possible to improve it. Attempted so far: I very gently cleaned the photoconductor drum with a dry wipe ( Kleenex l

Question by OuzoPower on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.