Pete --
The best commercial surface plate cleaner I ever tried was sold by Rahn. It was a soft, cream-colored paste in a screw-top tin can that sold for US$ 5 a pound twenty-five-plus years ago. Funny thing was that it looked, smelled, felt, and tasted just like . . . um, I've forgotten . . . DL, Go-Jo, Lan-Lin or one of the other national brands of waterless hand cleaner that the local fast-food auto supply stores offered for 1/10 the price in their weekly ads.
Because of the striking similarity between the Rahn cleaner and waterless hand cleaner, I tried the waterless hand cleaner as a surface table cleaner.
BINGO! For the past twenty-five years I've been using one or another brand of non-ammoniated waterless hand cleaner without pumice to clean precision stoneware. (The can I'm using now is Go-Jo Original from Ace Hardware's August Sale; US$ 1 for a big can.)
Scoop a bit out of the can, spread it over the surface to be cleaned, scrub as necessary with a "ok for Teflon" kitchen scrubbie, and sop up the mess with paper towels or shop rags. Works wonderfully well!
One word of caution: The name of the product is "waterless hand cleaner", but most of them are fundamentally oil-and-water emulsions. To avoid rusting you'll need to allow several minutes for the residual water to evaporate after cleaning your granite flat.
And for what it's worth, the old Rahn Granite was bought by Tru-Stone, which was in turn bought by Starrett. Starrett Tru-Stone still sells the Rahn paste cleaner, and the MSDS reveals that it's made for them by one of the major makers of waterless hand cleaner, Stockhausen if I remember right.
Here's a link to the Starrett Tru-Stone website page showing the Rahn cleaner:
http://www.tru-stone.com/pages/smp.asp#clean
And the MSDS:
http://www.tru-stone.com/pdf/rahn_msds.pdf
John