Hey Adalon - Susann is right, anything over 3 months isn't supposed to be bumped up. I really appreciate you trying to find the most recent post on this subject though.
Lots of these type of questions come up every couple if not every single month so go ahead and start a new thread. There are always lots of newer owners on here that can probably benefit from similar questions being asked or else clarification so don't feel bad about starting a new thread.
Again, I really appreciate you trying to not break the rules - I feel bad locking this!

But please do go ahead and start another thread.
To answer your question - I just have lots of rocks in their enclosures including a kind of rock called lace rock that appears volcanic. That keeps nails filed down, although I do find that the back nails are sharper than the front legs. They definitely drag themselves along more with the front legs!