I.have started soaking everything inthe hottest tap warse available eith a drop or two of dawn added to the worse.
I sort colors with like colors. So if there a bleeder or just a fabric with excess dye, it will not cause much damage.
Then I let everything soak in the hottest tap water available.for at least three hours.
Vickie Welsh ( I think is her name).has an excellent article about how she treats her fabrics before cutting them - and how to lighten or remove a bleed.
Will someone please post the link? I do not know how to do that on my phone.
I too had a dark red and a dark blue Jinny beyer fabric bleed when I sprayed sizing on some units sewn with light gray when I "just" gave the fabrics a quick wash in tepid water.
Then when I am comfortable that all the fabrics will have good manners when washed together, I give them a quick gentle wash,
i feel that crowding and over agitating the fabrics is what makes them look used.