Do you ever sew with material that you don't want to put pin-holes in? Suedes, leathers, vinyl, etc are often hard to work with without pins. Well, I have 2 tips for you!
First, you can use double sided tape. Then after sewing, you can pull the tape off into 2 strips by just by separating the seam a bit to access it. I don't advise tape though if your project is going to set for a while. It's more of a tape-it and sew-it the same day thing. You can also occassionally use masking tape to hold lighter weight and slippery materials in place. You can sew right over it and then just pull the tape off in strips when you are finished with the seam.
Or, you can use those hair clips that snap open and close by holding the one end and pressing against your head. Or, try binder clips. Depending on what you are doing, paper clips MIGHT work, but be careful if they'll pull off and gouge your expensive material.
Hope these tips can help you out. If you think of more ways to use tape, hair clips, binder clips, etc. please leave a note in the comments! We'd all love to hear them!