I have about 10g of pushing four year old ABV I found in an old tin in storage. It's been in an airtight 'smell-proof' baggy inside a large biscuit type tin. This has been in a temp/humidity controlled storage for the latter half of the time and normal housing before that. It looks like standard ABV, albeit a bit more crumbly than usual. No signs of mould etc. Do you think this would still be reasonable to use or I should toss it? I have about 9g of recently made AVB I was thinking of combining it with to make a lump of butter.