No nail polish in the house so I just put clear (scotch invisible type) tape over mine. The syringe will probably wear out before I need to replace the tape. I don't wash the outside of the syringe. Just suck up hot water with it 3 times before disassembling at the end of a mixing session. I have different syringes for different things--flavors, nicotine, PG/VG so no cross contamination issues and I only mix for myself so no critics of my method.