Was: How to make LoS from plain sulphur…
Which isn't saying much, since once mixed with water for use, LOS isn't very stable at all, lasting at most a couple days before it's lost a lot of it's effectiveness. I've seen some garden sulphur products that work, are already in liquid form, and appear to remain pretty stable over time. Unfortunately, that was a while ago, so I can't give you more precise product info...
I just recently bought some gel-based liver of sulfur from
CoolTools. The product claims to remain stable when exposed to light
and air. I’ve been using it on sterling silver and getting good
results. It’s fun to use–you can either mix a tiny amount with water
to make a solution or brush on the gel straight from the jar. Using
it straight, nothing seems to happen to the metal until it’s warmed
(I’ve been using an old hair dryer).
Then it starts changing colors. A quick dunk in cold water stops the
process just like with LOS.
It’s a bit pricey, but if it doesn’t go bad it’ll pay for itself
quickly. Here’s the link to the product.
(I’m not affiliated, just a happy customer.)