> Heating etchant ....
Fill sink with hot water from the household hot-water faucet/tap (probably
around 65'C .. just right for etching). Leave bottle of etchant in this
for 40 minutes or so. Perhaps replace the hot water half-way through, if
ambient temperature is low.
Start doing this an hour before you are ready to etch, and that's all you
need do.
mfc