Hot, hot water; check
Dish washing detergent; check
White vinegar; check
Mesh bags; check
Put some fleece in mesh bag.
Soak fleece in hot soapy water for 20-30 minutes.
Soak fleece in hot rinse water 20-30 minutes.
Soak fleece in not so hot rinse water with vinegar added.
Swing mesh bag outside to remove excess water and lay fleece out to dry.
Repeat until all fleece is clean.