I was about to toss the "gold mine" and "ghost town" signs
I make it a rule never to toss away anything I get in a mixed lot, because you can never be sure it might have a use later, or turn out to be some obscure piece of PM anyway. And you can get a LOT of junk mixed in with Playmobil (Sylvanian stuff can work well with PM though)!
The only exceptions to my 'keep don't toss' rule is any part marked:
a) Made in China (definitely won't be Playmobil!)
b) Duplo or L**o (put it in the children's boxes of these toys)
c) Macdonalds
Of course, not all PM parts have a distinctive logo or part number on them, but you can be fairly confident it isn't PM if its made of very poor quality plastic, especially if it has those spare bits of plastic where the mold parts join.