Is it OK to put backpacks in the washer and dryer?

Hello there, I'm curious about something. I've often wondered, is it actually okay to put backpacks in the washer and dryer? I mean, they're made of fabric and can get dirty just like any other item of clothing, but I'm not sure if the heat and agitation of the washer and dryer could damage them. What's your take on this? Do you think it's SAFE to clean backpacks in this way, or is there a better method for keeping them clean and in good condition?