Plus gas! Halfrauds may have some in stock. Otherwise any stock penetrating fluid. Apply, wait, apply, wait, apply - leave overnight. Should be OK after that. NB. What is 'stuck'? If you have the nut off the end of the axle, is there a hole though the other end? If yes, put a strong bar through there and turn, this should free the axle. If not, refit the nut to half its thread, then tap (thump) with a soft-faced mallet or, if you don't have this tool, use a peice of 1/2 (or thicker) softwood placed on the end of the nut and hit with a normal hammer. Once moving, it should pull through fairy easily. Remember where any/all spacers and washer fit for re-assembly!