Best stuff to soak this rusted bolt in?

The bilt hamber powder stuff you mix with water. Deox-c.

Oxy Acetylene! Lol

Auto trans fluid (ATF) and Acetone. Google it.

Id use a slitting disc to take the side of the nut off.

I've heard good things about ATF and acetone though.

The bilt hamber stuff will be no use for this job.

I've done this a few times and it seems to work, if you've got time:

Soak some cotton wool in plus-gas, plus-gas the nut and bolt liberally and then pack the wet cotton wool around both sides and finally wrap in cling-film as tightly as you can. Leave it for as long as you can and then try to undo it.

The idea is to stop the releasing agent from evaporating away, giving it a good soak.

If you can get either the nut or the head of the bolt in a vice and use a power torque driver, all the better.

drop it in some apple cider vinegar,occasionally scrub it gently with a brush,it will be bright metal in a couple of days,

I’ve just rescued a completely rusted up three jaw chuck with a day in an electrolysis tank followed by a week in a tub of diesel.

always had success personally with plus gas. heat shocking works well too. this... www.ebay.co.uk/sch/i.html?_odkw=rostoff&_osacat=0&_from=R40&_trksid=p2045573.m570.l1311.R1.TR1.TRC0.A0.H0.Xwurth+rostoff.TRS0&_nkw=wurth+rost+off&_sacat=0
does what it says on the tin.

fire!