It's hard to clean them. Manufacturers recommend cleaning stains with mild soap and water.... But in terms of cleaning whole blinds this would be hard. You could maybe take them down and wash each vertical strip in a sink, leaving it to dry, but depends on level of dirt on them. I had to try to clean damp stains (caused by condensation) off vertical blinds but had to give up the end and get curtains instead! Good luck.
iIwash mine in the washing machine - they were not 'classed as washable'
However i was them on a gently cycle with no softner added , after a short spin i iron them and then hang them on the line to dry
I have done this twice in 5 years and have had no problems - I remove all the plastic fitting and then just bung them in. My mother in law washed hers like this too and an old aunt says if you put them in a pillow case you eliminate the ironing of them.