Looking for your best practice for cleaning an enlarger lens with a build of "gunk" that a blower and brush will not remove

Hello all, A recent darkroom purchase included several enlarging lenses that had been stored standing up on a shelf without any covering. There is a fine covering of gunk (not fingerprints or smudges, just a fine layer of dust and ?)

First I used a jumbo blower and a blast from a can off Dust Off - it removed some of the dust / gunk.
Next I used a lens pen brush and gently whisked from the centre outwards followed by the jumbo blower - again it removed some of the dust / gunk.

Looking for your best practices and experience for removing the stuck on gunk.

As always thank you in advance!

Best regards

Todd

Most enlarging lenses are single coated. I'm assuming you can see the glass good enough to tell if there is any deterioration in the coating.

Since you have already removed any grit, the first thing I'd do is place a damp -- not soaking wet -- cloth on the glass for a minute. That should loose up most "crud". Then use some lens tissue to wipe it -- without much pressure.

Let it dry.

Then use a drop of lens cleaning solution or isopropyl alcohol on a new piece of lens tissue and wipe again.

Almost always a lens that "can't be cleaned" has damaged coating.