Use a dye made for polyester, such as disperse dye
Wash the fabric first to remove dirt, oils, and finishes
Set up a large stainless steel pot or dye bath
Fill with enough water for the fabric to move freely
Heat the water to near boiling
Add the dye according to the package instructions
Add a dye carrier if required by the dye product
Wet the polyester fabric before placing it in the bath
Submerge the fabric fully in the dye bath
Stir constantly to keep the color even
Maintain high heat for the time recommended by the dye
Keep the fabric moving to avoid streaks
Rinse the fabric in warm water first
Rinse again in cool water until the water runs clear
Wash separately with mild detergent
Dry the fabric according to its care label
Test on a small sample before dyeing the full item