Image from geekgirl24
Here are a few links to patterns that you may like:
+ Scrubby Bobbles Swiffer Cover (crochet)
+ Swiffer Cosy (crochet, and can be used with any sweeper)
+ Swoofer (crochet)
+ Nifty Floor Sweeper Cover (knit)
+ Swiffer or Clorox ReadyMop Mopping/Cleaning Pad (knit)
+ Dust Mop Cover (knit)
Seems to me it would be faster, cheaper and you’d have a more effective product if you used polartec type fabric and sewed these sweeper covers.