Dealing with paint and pitting

I got a 5-gallon cauldron from a friend who wants to put it back into use. No manufacturers' markings, but it's large enough and old enough to have two parallel gate marks on the bottom. It is either heavily pitted inside and out or was very coarsely cast. It has apparently been used as a garden ornament as it has also been painted.

I've had in the electro tank four days now (8 amp so it's taking a while.) After two days I noticed the paint on the outside starting to bubble off so I took a pressure washer to it and got most of the paint off. As you can see from the photos, the bottom of the pits are still black. I can't tell if this is paint or seasoning. Of course in order to cook in it, I want all the paint gone.

Any idea of what I'm dealing with here? My guess is to put it back into the electro tank. Any better ideas?

The shape says kettle, not cauldron or pot. The texture says rust pitting. I think sand blasting would be the only practical thing to do.

Hilditch

Sandblasting should never be considered on vintage cast iron cookware unless, as in this case, some other form of damage has already occurred to erase collectible value.

Well, that's actually good news. If it were a car, I'd be looking for a daily driver, not a garage queen. That I can use it and not be too fussy about it is a good thing.

Aircraft stripper or oven cleaner to remove paint then e tank

If the intent is to cook in this kettle and you decide to sandblast all the junk off it before seasoning, I would caution you to use new sand.
Used sand can get very dirty and carry that onto your cookware. It may look clean but, lets say a car rim was blasted first then you could get lead dust from wheel weights, Asbestos from brake dust, or paint chips from paint or clear coat that was on that wheel.
Don't get me wrong I think blasting is the most effective way of cleaning up a MODERN pan, but I always use new sand.
Good luck!
Tony