I have had a white slip covered sofa for several years. It is made of white canvas duck, cotton. If it gets dirty I throw it in the washing machine with a cup of bleach and detergent and it comes out beautiful every time. I have two cats and a dog and that's the beauty of being able to take it off and wash it, even though I don't allow them on the furniture, they are sometimes sneaky and do it anyways. Little buggers. Anyway I love it and have just hired a company to slip cover my two club chairs to go with it and can't wait till they are done.

I've had pure white denim slipcovers on 3 sofas in a vacation home in Palm Springs for 15 years. I love them! As dianefinn said, I simply remove them when dirty, put some oxyclean and/or bleach on them and they come out looking great. (They look better than the khaki Pottery Barn sleeper sofa I purchased at the same time for the den.)

I highly recommend them.

I am a total sucker for this look. To me it is warm and inviting and certainly brightens any room. Versatile to change the look with accent pillows etc... Go for it!