Fragrance free baby wipes and or vinyl cleaner will work on the canvas but very carefully test on a small spot first at the bottom of the bag. Don't use magic eraser on the canvas. as for the Vachetta handles Lovin my Bags is recommended for the Louis Vuitton Vachetta leather but other high quality leather cleaner / conditioners might be appropriate but you will need to be careful with that.
Also Regarding the canvas, it could just be the lighting. I purchased a pre-loved Damier Azur Speedy off Ebay and it would look dingy in certain light and then bright and pretty in other lighting. once you know you've removed all the surface dirt that may be there and you know that it's clean, decorate it with a cute purse charm and carry your bag with your head held high! : )