In article , G&M
writes
Just throw a bag of hydrated lime in a clean plastic dustbin, fill with
water (use ALL the safety clothing you can get) and leave for a month,
stirring occasionally. Not quite as good as some of the best lime putties
but good enough.

The problem is that you don't know how long it has been hanging around
in the builders' merchants, and how much of the hydroxide has turned to
carbonate.

J.
--
John Rouse