Wagstaff Extra 300
Sanding them will work - this can be tricky.
Use a 1" dia pipe- wrap sticky back 180 /220 grit paper around the pipe in a section abour 3" wide - until the dia is a smooth fit into the tube - auto shops carry this paper. .
using a twisting motion in the direction which keeps the sandpaper wound, move it slowly thru the tube .
Use some discretion !