After reading this question, I was left with the question of what happened to the ascent stage of the LEM after rendez vous with the CSM.
Obviously it didn't reenter with the command module, and I presume the service module was either left in earth orbit or deorbited safely, but the ascent module is (I assume) somewhere in orbit between Earth and the Moon?
Transfering the ascent stage of the LEM from the Moon to an Earth orbit would be a waste of very precious upper stage fuel. The fuel of the SM or the ascent stage.
The Apollo 10 LM is in a heliocentric orbit around Sun, this may be considered as a graveyard orbit.
A graveyard orbit around the Moon would require precious fuel too in order to lift the orbit to acheive long time stability. The masscons of the Moon cause an instability of lower orbits.
So the Apollo 11 LM was left in a low unstable Moon orbit. It finally crashed into the Moon.
The LMs of the missions 12 and 14 to 15 and 17 were intentionally crashed into the Moon to test the seismometers placed on the surface during the EVAs.
The LM of mission 16 was left in Moon orbit for about a year.
The Apollo 13 LM was destroyed during the entry to the Earth atmosphere.
See the answers to this related question.
