Some years ago I tried to develop a safe, cheap fluid that would work with all cartridges and aimed primarily at the AT ultrasonic cleaner, but we got good results with a brush. We seemed to avoid issues with capillary creep up the outside or inside of cantilevers, and it didn't dissolve stylus glues either. Inevitably to make it commercially viable (even at hifi prices!) it was based on a product from a different industry, which was changed so we were faced with either giving up, or investing a lot of time and money into redeveloping a niche product, and despite minimal packaging the bottle was the majority of the cost, but it did work really well. I'm heading for retirement, so maybe I may resurrect the project. Dry cleaning will never recover baked on muck and some cantilever / diamond combinations seem to gather more fluff than others. I've had good results with the green goop stuff like blu-tak but some cantilevers tend to hang on to some of it. Even the Linn sandpaper got some deposits off a stylus cantilever junction that nothing else would shift.