Try 28% Acetic Acid. Use rubber gloves and wash the areas well with water afterwards.
The stain is oxidized developer, which is soluble in acid.
PE
Very interesting, would this work on my Durst Printo with B&W developer crud that I get on my developing bath rollers?
Previously, when working in colour with the Printo, I had to clean the input set of rollers on the first developing bath after each session, otherwise minute amounts of crud would form and make pinhole marks on otherwise perfectly developed prints.
With B&W and the Printo, I usually clean the first bath rollers every other session, but it can be onerous, more so if the sesson has encompassed a few hours and sometimes the dropping of the bath and new one added as the paper throughput exhausted the first bath.
I currently use a product I purchased about 20 years ago directly from the USA, it is a darkroom soap like product, paste actually. This is applied to the rollers and rubbed in, and, in time, the crud and stains are removed. However I'm almost at the end of my supply.
Mick.
