Is there any way to remove old threadlocker off of screws? Thanks.

Many people go the cheap route and use a hobby knife or razor blade, and spin the screw threads down the knife edge. Acetone, found in a metal blue/yellow can at wal-mart, is the best cleaner for removing oils, build-up, etc from things like screws.

Personally, I use a die to clean threads because it does the job right the first time, and it is simple. I follow up a thread cleaning with acetone to remove oils. If you're going to spend any significant amount of time in this hobby, invest in a simple metric tap/die set from any number of online hobby and hardware supply shops. You'll use it more than you ever imagined.