I bought a cheap one from Target, and I use it for my every-other-day walks in warm weather. The problem is salt from sweat, especially on the shoulder strap.
There is no care label.
I asked a local dry cleaner, and they warned me their machines might break the metal clips. There are also a couple of small leather patches they said might be damaged.
Once, when a thunderstorm came up in the middle of a walk, it did get soaked completely (so did I). To dry it I just directed an electric fan at it, and there was no severe water damage when it finally dried out. It didn’t seem to do much for the amount of salt that was already there, though. Those leather patches were slightly stained, but not enough for me to care.
Wikihow says a machine washing should be okay, or if I don’t want to risk that, hand-washing. But the latter would be a moderate pain.
http://www.wikihow.com/Wash-a-Backpack
Agree? Disagree? Any other tips?
Could I get away with a standard detergent or must I buy a mild one? Can I do some kind of test beforehand to see if the standard detergent will damage the bag?