How to deal with the dirt on oblique canvas

Dear does everyone know how to deal with the dirt in oblique canvas bag?
You can try using a microfiber cloth (like the one used to clean sunglasses/eyeglasses lenses) and wipe at any dirt. Do not wet it as it can spread the dirt and allow it to penetrate deeper into the material. Do not rub the fabric as it can fray.

The Oblique canvas tends to hide dirt well as it has many variations in colour and is not very light at all.
 
I’m not sure if anyone has done this but a Teflon spray that is used to protect furniture might help protect the fabric from stains/dust.

Wondering if anyone has any positive feedback on this ?