As someone new to casting I think it would be of great benefit to have a list of things tried that didn't work. That will save many of us a lot of unneeded trial end error and let us focus on new things that might work.
For example I thought about using heavy aluminum foil for a gas check but I think I read on a post here that it dose not work. (what about glad press and seal?)
Another one was the idea to use dead car batteries for a source of lead.
Having a list to keep from re-inventing a wheel that dose not work would be mighty handy!