Any tips for the best way to get rid of the paint so I can fit the bottom bracket?

Steel wool & patience?
Nitromors and a lot of care?

Cheers

Stanley blade

Take it to a bike shop and get them to recut the threads and face the bb shell.

If it’s in the thread rather than on the face- got an old BB? Cutting slots in the threads of the BB can turn it into a cheap tap- thread it in (don’t force it) and it’ll hopefully cut the paint out for you, nice and easy. Does need for there to be a decent thread for it to take up in the first place though. (if it gets sticky, back off a little then go forward again- if still sticky remove, clean, restart)

What frame is it that’s got such crap QC?

Northwind, interesting idea there. I’vew got a rotary tool that will make short work of that. How many/wide is best? I might have to try it myself with a Raleigh AT20 bike I recently bought. There’s something wrong with the BB threads, they are too thick, and get worse further in, and have caused no end of problems removing/refitting my BB, including all the grease I stuff in there getting pushed out. The bike came with all the grease squeezed out as it was and the online retailer never got back to me with my grumbles.

If the thread itself is dodgy it’ll need a proper tool, the cut BB trick can chase dirt and paint and even swarf out of a good thread but it won’t sort a bad thread (since your “tap” is made of softer metal than the BB shell)

I just ran a hacksaw across mine about 8 times round the circumference… I find that clogs up very easily but, on the plus side, that prevents me from being tempted to force it. I reckon wider cuts would probably clear better though but never really felt the need to try it- not really something you have to do often.

But obviously if you hurt the thread you’ll regret it so if you’re unsure, worth taking it to a good LBS IMO.