I have done two Leica III cameras and an Exa. Most of the work was done by carefully scraping with some places heated gently with a hair dryer. I spent a lot of time with them as I didn't want to gouge anything or scratch any of the metal which wasn't covered. If you have to make any holes in the new covering, get a cheap leather punch of the right size then sharpen it as they are always dull when you buy them. Oh, and do like a carpenter measure twice, cut once. Naptha might help also, but it is very flammable and tends to run. Be very careful with any solvent as it can run into the camera and carry glue with it. It will be almost impossible to perfectly match the original covering so plan on doing all of the covering. If it's close no one will notice, also you can get some custom colors and textures and go wild as I have a burgandy Leica now.