Toilet seats are generally made of a soft plastic. Usually ABS (Acrylonitrile Butadiene Styrene) plastic, which is softer than acrylic, so a low cut polish is needed. Minor shallow scratches can be taken out with 1000 grit sandpaper then polish with McQuires No. 9 Swirl Remover. However, standard sized toilet seats are inexpensive, readily available, and easy to change. It may be more practical to replace them. But many seats found on higher end toilets are well worth the effort of repairing shallow scratches.