@Gategate 

In my experience, they are junk, rubbish, refuse, waste, scrap... 

Their singular, most redeeming quality is the first one/s is free, since they give you one or two with the filter.

... litter, debris, c**p, garbage, trash...

If you insist on using them, I suggest that if you roll them, roll them the SAME way every time, otherwise, they will fail you even sooner (NEVER fold them!)

... clutter, rummage, dross, oddments, flotsam...

However, they should last you long enough to buy a CNOC water bag, which is what I use and heartily recommend!

... jetsam, leavings, dreck. Get the idea?