Ahh the most dreadful part about being an avid vans fanatic and collector. It’s a complete love/hate relationship. Unfortunate when they get dirty. Canvas has been my biggest enemy for years. I own SEVERAL PAIRS. Some very rare mixed in. Do restos myself. There’s no fixing canvas once they are dirty, aside from cleaning and re-coloring which is very tedious. ESPECIALLY on any line of checkered. I have found out after several times and some trial and error. Now hear me out… still will have some fading and bleeding… but less significant I have found. When trying to clean. Try taking out laces, and scrub the shoe from the inside as best you can. Sounds stupid, I know. But it really does work a bit better and isn’t as hard as direct contact to the canvas.