*** Initially use some bathroom cleanser (the paste type) and an old toothbrush. Followed by Cillit Bang and an old toothbrush. Keep rinsing under wam water as you do it. After its been cleaned, you could immerse the brasswotk in some warm white vinegar for a wee while and again scrub it with the toothbrush.
Removing solder can be harder on old models but once its clean, a solder mop and a soldering Iron will take away excess, a fibreglass brush used stiff (with only a little showing) will clean up residues too. 2~300 grit wet and dry used wet also works - no matter hwat you do, its a tedious job.
C&L sell a chemical solder remover but use it with caution and of course neutralise and wash thoroughly after use or it will eat at the joints
Richard