I don't know what to do about avocado peals--we have a plethera of them and their pits, too
. I'm hoping someone else has some good ideas!
As for the egg shells, you can dry and then grind them up to a dust to add to the compost or soil as an amendment. If you have
chickens or ducks, you can also break up those shells and
feed them back to the poultry to give them calcium. We collect ours in an open container until there's
enough to bake in the
oven. During the winter we keep the container on top of the soapstone on our woodstove and when it's full we crush them up and give them to our ducks to eat. We crush them so they are small enough to not resemble eggs. From my understanding, the shells don't have to be baked to be fed to the poultry, but they certainly are easier to crumble that way!