How do you file a rat's nails?

My rats like to climb all over me, but their nails are really sharp and it hurts! Is there a way to file them down without having to actually clip them?How do you file a rat's nails?
The best option is to put a brick in the rats cage. A good idea is to place it where the rats walk a lot, such as under a food dish, or water bottle.How do you file a rat's nails?
Put a pruning log, something rough that it can scratch on like a cat does, in the cage and let nature take its course.





You have to be skilled to do this sort of procedure, especially on something as small and mobile as a rat. I do not recommend this. In fact, you should take it back to the pet store where you purchased it (if it has a grooming department) or to your vet, and seek professional advise on this.
You can put a smooth rock somewhere they walk a lot, like under their water bottle, but that won't keep them as short as you want them forever. Y'know, you'll have to still get them clipped every once in a while.
Put a smooth, clean stone under their water bottle. When they go for water, their nails will scratch the stone and file them.