Frozen breast milk is technically still okay to use for up to 12 months. But, if you'd rather not, you can use the milk in several different ways. Here are some ideas: - Use leftover milk to soothe insect bites, minor cuts, sunburns, diaper rash, and eczema - Create a breast milk bath for your baby - Mix leftover milk with solid foods - Create breast milk soap or lotion - Donate it to a mom in need