Annika, I did use Yes (Fairy washing up liquid) and warm water, even let it soak in it for a little while and used a sponge to try and get it off. I always turn to Yes first thing hehe. It didn't completely come out so that's why i posted. Icky stuff!! Yes should take care of everything.

I did spray on a surface I knew I could clean but didn't think about what I put the sandwiches on after.

I've given it a rest for today and will try your suggestions tomorrow, working from the easier/lighter to the harder/heavier stuff!