NO, NO, NO, Do NOT cut the threads that hold beads and such to clear them from your seam allowances and darts!! They are usually sewn in with a chainstitch (see the Threads article about that a few years ago). So, if you cut the chainstitch you will cause a "chain reaction" and soon beads will begin coming off every time you move the garment. The best way to get beads out of the seam allowance is to crush them with pliers. Wear goggles to protect your eyes from flying shards, perform this over a wastebasket, and give your hands a break every 10 minutes or so (so you don't get a cramp). Since beads are usually glass, they will eventually begin cutting the thread and begin unravelling all by themselves, so be prepared to nip that problem in the bud by saving fallen beads and sewing them back on ASAP, being sure to knot-off the chain of thread at both ends.