Possibly the reuse of glass bottles? Perhaps when something using a glass bottle gets eaten/drunk, you get empty glass bottles in return? Possibly have a way to melt them back down into panes of glass as well. Could do similar things with canned food, only it gives you scrap iron.
would have to have seriously deminishing returns otherwise it devalues the naturalist for finding iron nodes and then using the mine. so maybe a 25% chance to return unbroken items to be reused but even then only a 1/4 so basically instead of returning 4 bottles only have a 25% chance to return 1 bottle
