More people are thinking green and taking their own fabric bags when they go shopping. Canvas is a prime fabric for bags because it is sturdy enough to hold some weight, and a canvas bag can last and be reused for a long time. Keeping canvas bags clean is not difficult.
Remove all structural pieces from the bag, such as a vinyl-covered, flat piece of cardboard that fits into the bottom of some bags.
Fill a shallow bowl with water and dip part of the bag into it to test the canvas for colorfastness. Allow the wet portion of the bag to sit in the water for a ten minutes or so, then check the color of the water to see if any dye bled into it. Wring the wet part of the bag over a paper towel; if it bleeds dye onto the towel, it isn't colorfast. If it is not colorfast, spot-clean the bag rather than getting the entire bag wet to avoid damaging the colors. Do not wash the bag with other materials as the dye may bleed onto them. Skip this test if the bag is white or unbleached.
Pretreat any stains on the bag with laundry stain removers, such as laundry bar soap designed for this purpose. To use, wet one edge of the bar of laundry soap and rub it on the stain or spot. If using another type of stain remover, follow the manufacturer's directions for best results.
Wash and rinse plain canvas bags in the washing machine only if they have no decorative items sewn on or other features that would be damaged by machine washing and they are colorfast or plain. Look for a care tag inside the bag to determine the ideal settings for machine washing, following the tag's instruction.
Scrub the bag by hand if machine washing would likely damage the bag. Use a soft scrub brush or an old terry cloth. Dip the brush or cloth in a mild laundry detergent designed for delicates, mixed with warm water. Shake off or wring out excess water and, using a circular motion, wash the soiled areas of the bag. Rinse the cleaned areas carefully, taking care not to get non-washable areas wet.
Allow the bag to air dry on a clothesline, as drying it by machine may cause shrinkage unless the care tag states machine-drying is safe.