It's all-in-one formula is safe for your washing machine and provides perfect, long-lasting and intense colour results. Use copper to give your end result a greenish tint. Make a copper bath with a few old pennies (from before 1982) in boiling water, or buy copper sulfate online. Copper is toxic to consume, so don't use a pot that you use for cooking and work in a well-ventilated area. I dropped a had knitted white cotton hanging towel in a along with a good glug of vinegar… About 2 hrs later i have a lovely colored towel is a deep dusty Pink think almost maroon. script>