These cati belonged to my grandmother and have been on the same pots and "soil" for about 30 years. They are in desperate need of re-potting, but I don't want to mess it up. I have several cactus and succulents myself, so I'm somewhat familiar, but have not had to re-pott anything close to 30 years. Any tips on soil type, methods, advice of any kind is welcome to increase the chances of survival. Thanks!