I never had good luck cleaning the plastic shell of a 3.5 inch diskette; most of them have a thin liner materials inside, a type of plasticized frabric, that would disintegrate. So you want to use a blank, new, or otherwise unused floppy from which you remove the media and toss it. You insert the cleaned media into that plastic diskette shell. This is a very trivial operation, unless you're challenged in the hand/eye coordination department... Ok, again, perhaps we're having a communication problem. I have never tried anything other than what I described. Remove the messed-up media from its original shell and put it in a clean one. Clean the whole thing. This is what I've done, and your suggestion of partial cleaning has never occurred to me. And on reflection, I can't see any purpose in it. Unless you're reading into this some difficulty that isn't there. I would not make a recommendation regarding something I've not only never tried, but never even considered trying. Sorry! for 5.25 inch floppies, I've done that too, but even still, it's easier to use a donor sleeve than trying to get naked media into the drive IMHO, although YYMV, etc. -dq