As far as tanks go - the equipment in question is a set of four stainless steel open sided boxes that reside in another stainless box which acts as a water jacket. The four individual tanks have floating lids, indicating the chemistry that lived in them did so for long-ish periods of time. They also have covers that go over the lids. There are two print baskets that I assume were used to transfer the prints from bath to bath as you would with trays. I have a similar set up that I use with 4x5 hangers but without the water jacket. I have always called them tanks but perhaps that's incorrect.
The buyer did not necessarily ask for them to be cleaned but was curious about the compatibility between chemistries. This was really the core of my question and I should have been more clear.
If I have a tank (container) that once contained blix/color dev/stop/fix and I clean it so that it is visibly clean using standard methods (kitchen cleanser, scotch brite, etc..) will I be able to then use b+w developer/stop/fix in that container without damaging my new chemistry or worse causing some reaction that may be damaging to my health.
The fact that there are many things re-sold on ebay that have caused no trouble is an excellent point.
Many people know you don't add water to acid but always add acid to water. I was kind of wondering in the darkroom community if there happened to be an "Oh man, dont ever mix Blix and Dextol!, I thought everyone knew that" sort of thing.
All that being said, I started using
Dead Link Removed to clean these tanks along time ago. This product claims to remove all residue, cause no cross contamination, and be completely
harmless. It seemed to work great but I have not used the tanks ever.