Yes, there are several other natural methods for whitening sheets. For example, you can soak your sheets in a solution of 1/2 cup of borax and 1 gallon of hot water for an hour before washing them. You can also try adding 1/2 cup of washing soda to your washing machine along with your regular detergent to help whiten your sheets. Additionally, hanging your sheets outside to dry in the sun can also help whiten them naturally.