boil the kettle, add a few scoops of sod mets in to a spray bottle, preferably a throw away one. then quickly add boiling water, screw on the spray cap, shake (gently) and spray onto stain, then sit back in amazement as the stain appears to dissappear before your very eyes.
ps... wear a face mask and gloves. do not, and i'll reapeat that, "that" do not inhale direct fumes from the bottle. it'll take your head clean off. have fun.