Leveling materia - copying materia

Ok, so i found that I Can copy materia once its mastered. Does That work for summons as well as other spells?

Can You Level it Na just using it multiple times or Are there other ways to max 'em?

Solution 1:

For the best way to get AP for materia, go to the northern crater. Once you get there, go to the bottom (the room just before you fight jenova), but instead of going further down, go to the left and enter. There should be an enemy called "Magic Pot". To beat them, you have to throw them an elixir and then on the next turn hit them. You will receive 1000AP per magic pot you kill.

Every maxed-out materia will get multiplied (even summon materia), with the exception of MASTER materia.