QUOTE" I used laundry detergent and a scrub brush to remove stains from my sunbrella material. if its small enough, just toss in the washer.
then use the waterproofing and fabric guard to re-water-proof, etc".END QUOTE I would recommend that you do not use this advice.this is exactly what Raven Mills (maker of sunbrella fabric) recommends NOT to do.To answer your question Scotchguard is a better choice for an indoor fabric.Formula 303 is a very good choice and recommended by Raven mills however very very expensive.depending on the amount of canvas you need to protect ,there are some very good choices at a much more reasonable cost.I have a lot of canvas and the most bang for the buck with very good results is a waterproofing spray can that i get at Walmart in the camping dept.Aerosol can with bright orange cap for about $5 a can.does a great job!! Sorry but the name escapes me at the moment.If you need the name let me know and I will grab a can next time I am at the boat in a few days.You will still get the stains however they can be rinsed off with a garden hose used properly.For removing a stain on treated canvas ,first wet the canvas by spraying water on the stain while wiping your hand over the stain while saturating with water.Let it sit for a few mins and while still wet ,hose the stain with some force and if properly treated with waterproofing,most if not all of the stain will remove.Charlie