Spot on..Cass gets her Borax off the internet at a fraction of the cost.
As said above, but I would add that you should try to remove any fat or flesh that may be left, then allly the Borax. Massage it into the "cut" bit of the ear and work it well in.
Takes about a week to dry out in normal conditions.
Store in a sealed zip lock bag with one of those moisture absorbing pads that come with electrical goods and they will last for years.