Strap is stained- removing stains?

Although I have 50 watches and probably wear 15 of them, my Hamilton Khaki is my everyday beater. I've had it for 3 years, and probably wore it 4- 6 months of that time. Though it's a "beater," I treat it very well because that's what I do. I very much like the look of the strap. The canvas however is over a stiff, padded piece of leather. Once it has conformed to your wrist it is somewhat comfortable.

The issue is random splashes of water, usually from washing my hands or dishes cause bad stains to form. It's badly stained, and the whole strap is several shades darker than when I first purchased it. Does anyone have and tried and true methods for removing the water stains? The strap is about $100 to replace, so if I cannot get the stains out then I probably will just buy a new strap (not OEM, I'd be willing to spend $30- $40). Does anyone have any recommendations for a quality canvas strap, with no leather?

If I had the strap new I would probably spray a silicone water protectant on it.

I would ask strap manufacturer for care advice.

I wash my light-colored canvas straps in a mild detergent in lukewarm water; for anything with leather/leather backing etc, I use pure glycerine soap only, and let them dry naturally away from direct sunlight and artificial heat source. I always reconditioned the leather using something like Nikwax Waterproofing Wax For Leather.
The only issue that I encounter with this method is the cotton/linen canvas tends to get a bit faded, but I don't mind that look.
If I did mind that look then I would probably re-colour using indelible fabric pens. I hope this helps.