I use a clux and warm water and that does the job!

We used to have them at my parents place and I used to use the feather duster to sweep the dirt off. The duster is fluffy and light so you don’t need to put pressure on the blinds otherwise you may bend them . Close it first then gently sweep the dirt off .

Depends how stuck on the dirt is. There is a little cleaning tool you can buy to remove dust quickly and easily

If they fit, I’d soak them in a bathtub of warm water and detergent to loosen the grime and then wipe each blade.

Its a reals pain isnt it if you havent had a chance to clean them then when you get to it its just caked on and you run the chance of breaking them if you press to hard( i Know thourgh experince) I have found if you use something like mr scheen on them once you have manged to get them to a cleanish state, they are so much easier to clean the next time around as the mr scheen leaves a kind of glossy barrier on them.

I have to agree with STEPMOM but some washing up detergent applied first and soaped up, then hosed works a treat.
I have used washing up detergent or spay and wipe on the slates whilst they are still at the window in side but it is very hard to get the cloth along all the slates and cutting yourself is a real possibility. There is a cheap blind cleaning tool that is available from discount stores etc and it make cleaning inside easier but out side hung on the clothes line is a lot easier and gives a good job.
Also there are lots of tips on google. Best of Luck.

i was told by my realestate to unhook them, take them outside and hose them off.