Why does LOS have to be heated? How hot do you heat it?
You don't have to heat it. But it works a LOT faster when you do,
and you can use it in a more dilute mixture and still get the right
results in a short time.
Used cold may need it a bit stronger, and will usually take a good
Also, while this doesn't apply if you're using the newer LOS gel
products, if you use the traditional solid pieces, you'll find
they're quite slow to dissolve in cold water. In warm or hot water,
they dissolve quickly enough. As to how hot? Don't boil it, as that
just increases the rather nasty smell. Anywhere from as hot as the
tap will deliver to just below boiling is good. Hotter is faster.