Will wrote:

SNIP

But, you can still do your own gas work, so you could legally switch
the gas off at the meter and insert a cap, then re-plumb your gas as
needed, connect it back up and test it with leak detection
spray/washing up liquid solution.

SNIP


I bought some of this detection spray, but the instructions on the can
are a bit vague. I assume given contact with gas the liquid/foam will
solidify, otherwise it just runs off as liquid?