crimsonking

So I was going through some old leather stuff and found I still had some brown dye, leather balm and gum tarcaginth (spelling?). My question is I know they are at least 5-7 years old are any of these still good? Some of them are still in the plastic bag they were mailed to me in and unopened while others have been open but had lids on the the whole time.

Or would it just be better to spend another 30 or so at tandy to get one in better condition I normally wouldnt worry about trying to mess with it but its a pretty big chunk of a hide left and dont want to just throw it away

Ok so Im working on a suit of leather armor and I have an old hide that is thin enough to use for a certain part of it. Only problem is this hide is old has a bit of mold and is a little stiff (it doesnt roll up really it sorta folds) but its not rock hard and still has give and pliability to it. What (if any) steps should i take to clean up the hide, get rid of the mold and get it a bit more flexible again? Thank you all for the info in advance!