Avoid washing multiple garments together. Turning the garment inside-out will reduce fading but won’t prevent the colors from bleeding.

Ideally, the water should be at least 140 °F (60 °C). [3] X Expert Source Kamel AlmaniLaundry & Cleaning Specialist Expert Interview. 9 April 2021. You don’t need to add detergent to the washing machine, but it won’t interfere with the shrinking process. Only add detergent if you’re looking to wash the garment as you shrink it.

Note that the more often you wash and dry the garment, the more color fading you may notice. Only attempt this a few more times. If you still cannot achieve significant shrinkage, consider using an iron.

Do not use a steam setting on the iron. A dry iron will dry out the polyester as you pass over it, which is the effect you’re looking for.