Be cautious when sewing certain fabric, like satins, certain light knits, vintage fabrics, etc. Safety pins have a larger diameter than straight pins and some will leave permanent holes in satins, and vintage acetate, vinyl, leather and being sharp can cause a very fine knit t have a tiny hole that unravels and ruins your project. my suggestion with these delicate fabrics is just to roll them up out of the way, or stitch a few stitches at a time checking to make sure you haven’t gone over the wrong part. I have also used quilting pins which are smaller in diameter and have a bend that makes it easier, but still, not on delicate fabrics.