The spools that I purchase are 40 yds. The netting comes off the spool at 3" width. Before I do anything, I use a Cutco bread knife (really works!) and cut the spool in half, just as if I was cutting a loaf of bread in half, right down the middle.
After this is done, I have TWO-1.5" wide spools. Each are still 40 yds in the length. I can get 3 scrubbies out of this spool.
By the fact that I've cut the 3" spool in half, I get a total of 6 scrubbies out of it all. So I'd say each scrubbie uses approx. 13.5 yds. of netting.
If you want to knit "netting only" scrubbies, just knit the 3" width netting as it comes off the original spool. You'd only realize 3 scrubbies using the 3" width in this way!
Here is the websitewhere I purchase my netting!
Here's what their nylon netting page say to reduce the width from 3" to 1.5":
"Need to cut your netting to a smaller width? No Problem!
Make marks with a pen on the cello wrap all around the spool. Take a fine serrated knife such as a bread knife or a fine toothed saw and cut through the netting all away around the spool, down to the cardboard tube. Then you can take the wrap off one side but leave it on the other so it keeps the netting in place until you are ready to use that side. An electric carving knife will act like an electric saw and works well too if you don't mind moving parts!"