I have tried 'em all save the Keith Monks and the other super-high-cost cleaning machines. Without a doubt, the best method is the Disc Doctor System, and I say this not out of user pride, and nor do I enjoy cleaning records this way. But if you really want a clean record, this is the best way save the tooth brush method, which is far more than I am willing to deal with to clean a record. I'd go back to CD before that.
The other day I asked my friend to bring over a recent copy of a record he had purchased specifically to use as a demo disc for various systems. It was used, but upon close inspection, it looked pristine. Nevertheless, as we all know, looks can be deceiving: Rice Krispies.
He had cleaned it thoroughly with a very powerful homemade vac and his own solution, several times over. He is an engineer, and a fastidious one at that, and his DIY cleaner is far more powerful then is the thing NG sells (and which I bought). Anyway, I also gave this LP a crack on my own RCM (Nitty Gritty), just in case the fluid was somehow at fault: Rice Krispies.
That was weeks ago. Fast Forward to earlier this week:
I showed him the simple DDr. method, and in 120 seconds his record was getting a final rinse on my Nitty Gritty. His jaw dropped when we heard the results. Sure there was some noise on the record, but nowhere near its previous state, and now he has an LP that is at least worth what he paid for it, in that it can be enjoyed, and is in excellent condition and near mint on many grooves. In any event, its conditon was transformed from a blight to a light.
Another nice thing about the DD is that once done you only need to store it. A second cleaning is rarely necessary, and usually redundant so long as you use an anti-static brush before and after playing.
The only other solution that comes close is the Record Research Labs, but having used those and all the rest, the Disc Doctor is the best. It is FAR less cumbersome than the directions might lead you to believe, mostly becuase the brushes really take to the grooves. You feel as if your work is going to be worthwhile.
It is so good that any records previously cleaned with anything else get a DD treatment before they are played on my better cartridges.
As an aside, I run a Shure V15VxMR as a budget cartridge and will often not bother cleaning some of my non DD cleaned records, preferring to deal with the few blemishes here and there in the interest of saving time.
But, for ALL critical listenening, the better arm/cart/table is fired up and even new LP's get DD'd. This is the only "absolute truth" in vinyl, at least until somebody can invent and market a RCM that does the DD one better, I state it without equivocation. Wish it weren't so, BTW, b/c I HATE to clean records!