I think it's a good question, I have been doing some research on the same topic except for focusing on collecting and drying wood straight from the tree. I have collected a few pieces from local waterways. Pretty much did the same as others washed the mud off, soaked it for a while and then put it in my tank. One thing I would do is take some sort of hand saw with you when you go collecting, often a piece is overly large and you can't or don't want to take all of it. Also you may want to take a measuring tape and have an idea of what size pieces you are looking for.