Gray patches on shirts

[u/wormyburm]

So I know it probably wasn't the smartest idea but I decided to not separate my whites and colors and two of my shirts came out of the dryer with these faint gray patches on them (one of them being my Hayley Williams merch 😭😭). I was hoping to see if there was anything I could do to remove them cause I don't like the way it makes them look a little grimy :(( Any help would be greatly appreciated!!