Which cleaning solution do you use in you RCM?

Window Cleaning fluid from my car.
Works well and is cheap

I agree with Rushton and I add MoFi enzyme to the list as a second when I am in a hurry or on new. The walker is a time consuming process but does a great job. I just get some headphones and listen while I scrub and 10 or so records to make the mixing worth while.

I love the Audio Intelligent the best so far, over RRL and MOFI. It's just made my records quieter. Can't comment on the static factor. I use the #15 and then their water rinse. They do have a 3 step, but that and the Walker 4 step would prevent me from cleaning at all.
One thing, do not put anything in your path that prevents you from using your RCM, or table for that matter. I learned that from the great Gene Rubin years ago.

Compared to my experience with Audio Intelligent,Disc Doctor & VPI fluids, Walker Prelude is best by a very noticeable degree. I hear improvements on LPs that were cleaned with AI. Also, I find that Walker Prelude is fast, even though there are 4 steps. Each step is fast. With AI, I had to leave the enzymatic solution on far longer to get it to be effective. I am no scientist, but perhaps there is merit to the idea of mixing the enzyme powder w/water fresh each time you use it, as I do now with Walker Prelude. Cheers,
Spencer

STEAM! Followed by a little AI rinse. I am finding that with steam cleaning there is very little if any need for an enzyme cleaner.