Naturally, I am not sure, which topik summarise my problem the best, so, I ask the question here. I found out that Mozilla browser takes a lot of memory in my smartphone (like no one app else). Cleaning up the cache didn't help much, because the most part of memory is taken by the "user data". Please tell me what exactly is it, what parts it consists of and how to clean it avoiding the ability to remove anything important. Thank you for the fast answering and for operativity Korwin