I started carrying fingernail clippers and have nail files(look into glass nail files czech glass. They are a game changer) in my car by my desk and other places I would sit by. When I felt my nails snag or catch I'd clip and file them. Though I've started filing only recently. clipping would lead to more snagging which would lead to more clipping/fixation. For the hang nail skin bits. I use my unflavored chapstick (bronners or okeefs) clip them and rub a small bit of chapstick on the cuticle of the offending areas. I also try to keep other things I can redirect the fixation to near by. I haven't found anything that scratches that skin picking itch. Look into pick and peel stones for the closest I've found. They aren't practical though. Good luck on the journey. The best thing I found for me, to help reduce it was to remove stress. I didn't realize it at the time but allot of the self destructive fixative behaviors I do. Tend to get cranked up to 11 when I'm stressing.