What you need: Mannequin head, Hair clip, Water, Conditioner, brush and a Flat iron that does not get super hot.
All you do is work in small sections, moisten the hair with water + conditioner then flat iron the hair piece. (if its curly use a gentle curling iron and follow the curl pattern)
Keep the fixed hair separate from the un fixed hair (use clip) The smaller the sections the better the results! This will make your synthetic hair look almost like new! No need to throw it away or waste money! Enjoy!!