White towels, sheets etc should never be washed with anything else but whites. My dear old aunt said so. I made a call to Sicily because I remember pots of water and sheets boiling Her instructions were similar to Mats except we had some huge copper kettle, filled it with water, boiled it (we didn't have hot water back then) left soapy sheets and towels over night then washed as normal. You can do the same in washing machine. Good soaking is the key. She said you can also soap them up and place in the sun but only if they are 100% cotton.