On 03/08/2016 18:57, Cursitor Doom wrote:
I've found Plusgas and all the other so-called "releasing agents" to be
totally useless, to be honest.
This looks like a job for an impact driver. I'd be reasonably confident
about getting them out with one of those, having previously had
consistently good results with them.

I was having trouble getting a screw loose on a bracket what I did was
use my cordless drill on a low speed low torque setting and increased
gradually so it wouldnt strip the head. I was quite surprised that it
loosened it, maybe just luck but it worked.