Just my experience, I once did a trial where I took two identical 5,25 inch disks of the same batch from the same manufacturer. These were clean disks which both formatted and verified just fine, but I wanted to see if IPA did indeed damage the disk.
One I swabbed one with 75% IPA, the other with warm water with a touch of dishwashing liquid. On checking the IPA swabbed disk now showed a few damaged sectors. The water/detergent one did not. It's not scientific (just one rep) and I was quite aggressive with the wiping. However, it made me steer away from IPA. Immersing the platters in warm water with a touch of detergent, and gently wiping (then air drying) works well for me when cleaning "dirty disks". Terry (Tez) On Wed, Jul 11, 2018 at 8:17 PM, Steve Malikoff via cctalk < firstname.lastname@example.org> wrote: > Fred asked > > What concentration of IPA were you using? > > 99% Laboratory grade. Not very pleasant to have on the skin, it dries it > out shockingly. > > > There might be a difference in results between 70% and 91% > > > > There might also even be a difference in the oxide formulation between > > brands. (If Chuck was trying to clean a Wabash, then it might dissolve > > right through the plastic.) > > I've had Computer Resources, Wabash and other cheap diskettes long ago, > they were > none too good. Verbatim and Dysan always seemed pretty reliable for me. > >