Vacuum with the brush attachment on your vacuum cleaner.
Here's a video tutorial: https://www.youtube.com/watch?v=zqr4l-o-ylI
Hi Susan: Here's a site that may help: https://www.youtube.com/watch?v=ySkxEpb6ysI Good luck
Just vacuum them well using the upholstery brush. Start at the top and work down. For spots you'll need to be very gentle and dab with a very diluted water and soap mixture. Don't scrub the blinds, just dab at the spot and support the fabric from the back side of the blinds so as not to damage them. Using another cloth, rinse the area to get rid of any soapy residue, all the while dabbing rather than scrubbing or rubbing.