Please help me. I'm 73 years old. I have been dyeing things for decades. I live in Hawaii and have 350 very beautiful aloha shirts. A small amount of these were used. In this part of the world, the sun is very, very strong. Plus being at 3,000 FT. above sea level, the sun really gets strong. Some of these shirts were put in the sun to dry, something I would never do. Well, the outside is faded, but the inside of the shirts is like brand new, full of colors.
When I was a young boy, I remember a process of soaking a damaged shirt like this in some kind of solution for about a week. I cannot remember what it was. It was not Woolite. I don't think it was vinegar, but it could have been a mild bleach solution. The colors would blend back to the other side. What do you think?
You know a good seamstress?
I have tried several solutions to try and restore some color to the outside of some clothing but few worked really well. One of the problems is the type of material and many of the style shirts you mentioned are made of synthetic material (polyester, or blend with cotton) and some are silk so each one would probably react differently.
Tide makes a product called Rescue. Here is the link: amzn.to/
I'm not sure this would work because you have so many colors on one shirt, but you could try it on one shirt and get back to us.