Steps to Dust Blinds:
Dusting vertical blinds regularly, as you do the rest of your home, will keep them cleaner longer. Use a duster that lifts the dust right off the blinds rather than on that moves it around, such as a rag. The Fuller Ostrich Feather Duster or Swiffer Dusters are good choices here.
You should try to clean vinyl slats without taking them down. If your blinds are getting older, the plastic is probably getting brittle from exposure to the sun. By removing the slats you might end up breaking the clips that they hang from, or slats can break out at the top where they clip into the rail.
To clean your blinds in place, just wipe them with a damp cloth. Using both hands, wrap the cloth around the slat and wipe from the top down. This is also a good way to remove static electricity from newly installed slats that are sticking together and not hanging straight.
When cleaning, be careful not to use anything abrasive that might scratch the vinyl.