OK - this may sound nuts and I haven't tried it - hope not to have too - but maybe if you catch him spraying and clean it up right away try using "club soda". It gets out red wine and everything else. It is awesome and cheap. It may get that out too. It is better than the OXI clean stuff... May be worth a try and won't hurt anything as it is only oxigenated water.... Just an idea.. Debbie