Is it dirt, or is it grease, or both? The first thing I would try is brake cleaner sprayed from the inside with a towel held to the outside to keep the waste from running down the canvas. 

If that only works so far I would then scrub it with dish detergent and spray it with shout after rinsing the detergent off well. 

Jim

Sent from my iPhone

> On Jul 6, 2021, at 9:23 AM, Thomas Casal <thomas.casal@gmail.com> wrote:
> 
> Hey volks,
> What do you guys do to prevent the hinge dust from soiling your pop top
> canvas? I have a few year old canvas and it looks terrible with that hinge
> dirt on it. I don’t even know if an upholstery cleaner will clean it. Peace
> Tom