You can reshape the material by standard methods. Using sandpaper, I would suggest starting out with 220 and then 400 and then 600 and finally 1000.
The black wet and dry sandpaper works the best if you use it with a steady stream of water that will keep the paper clean.
The only difference between the dobro/reso thumb picks and our regular thumb picks is blade thickness. The regular thumb picks(BCT-1L, BCT-1M, BCT-JDL, BCT-JDM) have a blade thickness of .0050″ or 1.25mm. The dobro/reso thumb picks(BCT-RESO-JD, BCT-RESO-JDM) have a blade thickness of .0060″ or 1.5mm.