How To Wash A Dickies Backpack Do You Think This Would Be Safe In A Washing Machine?

Do you think this would be safe in a washing machine? - how to wash a dickies backpack

Hello, I have a backpack Dickies and white with splashes of color on them (see link)
http://www.grindstore.com/products/Dicki ...
The dirty, because who knows, it really shows.
The instructions say to wash, wipe with a damp cloth, and I tried it and its still dirty.
Do you think it will be good in the washing machine on your own on a cold plate.
Or if not, any advice on how to clean?
Thanks in advance