This is probably a really basic question but I'm very inexperienced in
dealing with metalwork.
I've just had a leg-cum-support made up by a local metalworker for a
fitted worktop-cum-desk I'm making; it's just a couple of lengths of
square-section steel bar welded together at right-angles. I want to
paint it now, but of course it's in 'workshop' condition, covered in
grease and surface. Before priming, how do should I clean and
degrease it? Polyclens then water? Meths or something? Does it
actually matter? Anything else I need to know about?