Tooth picks and spray can oil? It should help dissolve things, a drop or two of white spirit in the right spot can safely be used on all metal parts. The risky thing is the beige paint, it had to be done carefully. You might have something usefull on a shelf some where..
For stubborn stains I have used warm soapy water and microfiber cloths, it works well and my 201K23 turned out clean and shiny after. It should do a good job. For the inside where there isn't any beige enamel paint you can sort to stronger stuff.