I keep my new needles in a lidless recipe box separated with tabs saying what the needles are (embroidery75, embroidery 90, quilting, topstitch etc). When I take a needle out of the box, I clip a clothespin to the tab I took it from. I have several clothespins, each marked with a Sharpie for one of my sewing machines. I only save needles that have been used VERY lightly, and they go on a tomato pincushion marked into sections for the various needles that I use. If you think about it, needles are probably the least expensive thing that you use, and it's simply not worth it to ruin fabric or a machine with a needle that's dull.