If you have a sewing machine use a zig-zag stitch completely around the edges.

I sometimes use masking tape. I don't know what they call it in the UK

I once used Fray Check on a pair of slacks. I did not use a test area first. Unfortunately, it made a mess when I washed the pants. I would not recommend it.

I agree with NancyeG. I sew a small hem around my project if it is a large one. if it is a fairly small project I use masking tape around the edges. I also tried Fray Check once and didn't like it at all so threw it away.

I use Fray Check and have had no problems, but I use it very carefully and sparingly. I use acid-free masking tape for my edges, as my old trwadle machine does not have a zigzag stitch. It does, however, keep my ankles slim and trim...lol.

I have used both Fray Check and Fray Stop and never had any problems. Like Su said, use it sparingly and it works fine. I've also used diluted white glue (i.e. Elmer's or Aileen's) and not had any problems. The trick may be to use as little as possible.