We offer over dyeing to black on the last Friday of each month only. Garments for this service must be received by the 23rd of each month or they will be held until the following month. We do not offer rush service for dyeing black. Polyester and polyester blended garments will not be able to go a true black as polyester does not dye. Polyester thread will not dye. Garments may shrink due to the amount of time they need to be in the vat to go black. We do not dye wool coats or garments black due to shrinkage. We cannot guarantee the darkest purest black on any items for any number of reasons.