This is the sure, safe, commonly accepted advice... Too much work for a $20 drum – IMHO.
The low-effort – Thawley approved – method is to get the paint to just peal off the inside. For that you need a LOT of heat. You'll never get enough from a fire built
inside the drum. The fire just can't get enough oxygen in there for a really REALLY hot burn.
I burned the
Ultimate Ugly Drum Smoker™ from the outside in. Just got me a genuine
HF weed burner, a full tank of propane, one of them nonflammable Budweisers and put the hurt on it. Once cooled the paint flaked right off with a stiff wire brush. And I had another beer.
Unless you're after that oh-so-desirable antique patina, it's probably best to paint it before winter.