Cleaning Mini-Blinds
When my mini-blinds start looking like they need cleaning (or else in the two weeks I do heavy housecleaning before a family holiday dinner, 2 or 3 times a year), I take them down, run warm to hot water in the tub deep enough to hold 4 sets of mini-blinds, add about a cup or so of dishwasher detergent, and about a cup of ammonia. (With your blue blinds, you might skip the ammonia.) Lower the blinds into the water, swishing them up a down a time or two, and walk away. Come back a couple of hours later (during which time I clean the windows – I have the kind that drop in so I can clean the outsides also, and at the same time I put the curtains through the washer & dryer.) Rinse thoroughly; stand up in the tub so they can drain. Come back an hour later, and hang the blinds. They will not have drained thoroughly dry so some of the slats will stick together and you have to plop them with a finger to get them to come apart.
I do this 3-4 times a year, and my white blinds look absolutely sparkling when I re-hang them. No streaks, no smudges, no having to wipe down each slat. And my windows and inside window frames are clean – which is so much easier to do when the blinds are in the tub and the curtains in the washer and dryer. My curtains do not need ironing or dry-cleaning, so I can just re-hang them after I re-hang the blinds.