are we talking about the inserts or the bag itself?
the bag itself being is made of canvas and synthetics, and can be washed like other havasacks. dumped mine into the washing machine and came out very much alright. i guess it also makes sense that being water resistant it was designed to get wet.
about the inserts, i only hand washed those because i noticed there aren't additional stitchings across to ensure the fillings inside doesnt move (like a quilt). no problems mantaining the shape hand-washed as well.
no ah never soak. just dump straight in. i do not put the sponge inserts inside the washing machine, i hand wash those. not cos of the detergent, but because i'm worried it might loose its shape.
don't fret just dump your bag in! haha i know the bag isn't cheap and was apprehensive myself. but i've been washing my hiking bags this way since forever - and those bags collect a lot more grim than camera bags.
hey hey hey...
hiking bags are way better to be washed hosed down...not only do u save water but its waaay more thorough!!! all the dried sand and grit and mud!! inside the little seams and nooks and crannies...its really better to wash with hose and hang upside down to dry...same with ur lowepro...
waterproof stuff have either nylon inner linings, or are nylon or synthetics themselves..or they are pretty dense, like 1000D or more..better outdoor gear have extremely micro layers of synthetic wax or something melted and bonded onto the external layer..its best to handwash and take care of them..and u can buy waterproof sprays for them too..i dont use them but iv seen Timberland sell those small green bottles of squirtsquirt type bottle, for waterproof care..