Do NOT use sulphur strips that is highly undesirable flavoring. If you are nervous
about the interior, consider a boiling hot water rinse or perhaps some burbon.
(if you rinse it with some mild burbon or vodka, you can re capture that and still have
a good snifter or 2....its not like its goin to be bad)
I would also drain the thing, give it a good assessment with your smeller....
It should be woody and sweet, not musty and foul.
You want to avoid mold mostly. If you are going to sour it, you are going
to infect it with a bug of your choice anyhow. So... If it smells good you are prolly
good to go, hot water rinse and fill with beer....sounds like they took good care of it for you.