Eleanor, Ronny,
The tutorials you did are good as is this forum. Everything I have seen here though is pretty much vertebrate related. Many of these techniques can be scaled down to apply to invertebrates but I find, at least here in the Cincinnatian, the techniques required are different. It is quite easy to damage or destroy a fossil in the cleaning process by using improper methods, improper materials or poor technique. One of the most important things we need to know when attempting to clean a fossil is when to stop. We also need to know what the matrix is made of and what the fossil is made of. Around here, both are primarily calcium carbonate precluding the use of acids for cleaning. Dental tools have been suggested for years and they are fine for rough cleaning but when you get close to the specimen surface they are too big and clunky. As you mention, magnification is a must and really fine cleaning requires a stereo microscope. Even in this area, different fossils require different cleaning techniques.
I am attaching two photos for your consideration. One photo is a crinoid that I hand cleaned with tiny pins and water – a technique I was taught by Prof Colin Sumrall of U of Tennessee when he was curator at the Cincinnati Museum years ago. The second photo is the same crinoid after a dusting with an air abrasive unit to remove the last film of dust. The original surface was completely filled in as you see at the top of the specimen. This process took many hours but the surface of the specimen is intact.
Would you recommend a separate forum for cleaning techniques for small invertebrates or do it all in this one?
Jack