I have a rackpack that is only held on by four Velcro straps. They've held very well through daily commuting through the summer and fall, even through a lot of wet weather. But it seems winter riding through snow, slush sand and salt have been too much for them and now they don't hold anymore.

Can anything be done with them to make them usable again?

Can you just buy some new velcro and sew it on? I have done that with other things before.

The velcro that has failed on me has failed because the loop part was cheap and the strands pulled out. If that's what's happened, buy new velcro. Actually, if it actually were "velcro" it probably wouldn't fail like that. The stuff that fails like that is crappy fake velcro-like stuff.

I've had it fail due to the hooks getting full of crap from other pieces of clothing; in these cases I've been able to restore it by pulling the crud out of the hooks with a needle or other bit of wire.