Any fixer splashes quickly corrode my (not very) stainless steel sink. I've found the 'cream cleaner' type kitchen cleaner (The 'premium' brand is Cif (what was wrong with Jif?) in Europe, it's the chalky Scours Without Scratching! stuff) is very effective if used at the end of each session. I'm not sure if it's due to the calcium carbonate in the cleaner neutralising the acid in the fixer ('O' level chemistry was a long time ago), or just that the white chalky residue left behind if you don't thoroughly rinse down means bits don't get missed.