First advise : prevention is of course the best, but not always forseeable.
Second advise : try to prepare recipients for doggy bags (if people tend to live far away, aluminium lasagne-like recipients are wonderful.
Third advise : throw away everthing which will certainly not be eaten the following days.
Personally I prefer not to eat already cooked leftovers, but I cannot throw away food. ;-).
As lunch on the following day a lot of food can disappear and will sometimes be even better.
Other dishes can be changed in something different even so that you don’t really get the idea that you are eating the same food.
In this case : humus and open-kibbeh leftover plus 1 egg, pepper and salt will be worth to bake in balls, with some salad and some Greek yoghurt( with 1chopped garlic clove, pepper, salt and chopped fresh parsley).