So you have a nut, bolt or screw that is in good condition but it just won’t budge, if you have a mangled or stripped screw or bolt have a look here, otherwise you are in the right place.
One solution is WD40, spray it so that it runs down the thread of the of the bolt your trying to remove and leave it for a good 10 – 15 minutes at least.
You don’t have any WD40, hmmm. You could mix some oil and white spirit and pour it on the bolt.
The way this works is that the white spirit thins down the oil letting it run down the thread of the bolt. The white spirits evaporates leaving only the lovely slippery oil.
If you have any other suggestion, to links to similar info then let me know.