What Laundry Symbols Mean And When You Can Ignore Them- hand wash cold symbol ,There is a big difference between a laundry tag or laundry symbol that says "dry clean only" versus one that merely says "dry clean.." ...... when a laundry label says "hand wash," this means it should not go in the washing machine, even in the delicate cycle.. ...... An important rule for anytime you are considering ignoring laundry symbols or laundry ...... Science Laboratory Safety Symbols and Hazard Signs ......10.. Wash Hands.. Hand washing is a primary safeguard against inadvertent exposure to toxic chemicals or biological agents.. The wash hands safety sign lets lab personnel know to wash their hands after removing soiled protective clothing, before leaving the laboratory, and before eating, drinking, smoking, or using a rest room..