Sorry that this is a bit gross, but I need suggestions please 
When my dog shakes, any 'juice' that might be on the end of his penis flicks off onto surrounding surfaces. We're talking smegma here. Bless him....!
The marks won't come off of my leather sofas. Obviously I've cleaned the actual substance off, but there are still little marks. I've tried leather cleaner, baby wipes, Zoflora (of course, this is Mumsnet) and Dettox.
Any other ideas?