As a sushi chef i have several japanese whet stones which i use to bring all of my knives to a razor sharp edge. 
 
ive seen plenty of tutorials on how to lap a CPU all of them using sand paper and a sheet of glass. so i wondered if i can skip that by using my whet stones.  
 
i would like to point out now that these whet stones were very high quality with a hefty price tag to match them. so as far as value in doing so sandpaper and glass will still be much more cost effective. i simply had these available to me. 
 
the whet stones ranging from 600/1000, 3000, 6000, and 8000 grits

 
The test CPU will be a old P4 i had laying around. 

 
All edges taped up ready to lap

 
After a few swipes on the 600 grit stone you can see the high spots on the sides being worked off first. 

 
fast foreward the work to after the 1000 grit stone we can see the level surface and all the copper on top exposed with several rough scratches.

 
After the 3000 grit stone we can see the cpu has a nice matte finish. 
 

 
Fast forward to after the 8000 grit stone, the CPU has a nice mirror finish with a few micro scratches. 
 



 
as you can see it seems that the corners have been ground down slightly more than the center. i dont think this would be an issue however. 
 
 
Does it work? Yes, however whet stones have imperfections in them resulting in the micro scratches... even with my expensive 8000 grit whet stone i cant get a perfect mirrior polish which i could using sandpaper. 
 
would i recommend this method? No, glass and sand paper is probably still much more more cost effective and probably better in general.
 
At any rate. i have no clue weather or not i had a performance increase.. this cpu has been sitting around for several years.. since i had no mobo for it i never even check to see if the cpu was working. i kept it well protected and there are no visible damages however i dont have the hardware to test it. 
 
this was posted jsut to show the results of using Japanese whet stones for lapping. 
 
Enjoy.

nice finish. i use 80/120/1000 sand paper then finish polish with fiber optic polishing film. did you wet sand or dry? i use distilled water for the final polishing, works great. 

lol yes as loveha said.. they are whet (wet) stones..  so to preserve the stone they are used wet.
 
 
for whatever reason when purchasing them they are spelled whet instead of wet or rather whetstone.. without the space...  ive seen it both ways but from traditional Japanese sellers they are spelled whet.. so i just follow their terminology on that. 

lol!  id love to. tho i dont think you will enjoy it as much after the shipping.. sorry i dont offer overnight shipping  standard USPS priority 3-5 day shipping only.. .. i gotta assume Oklahoma is one of the worst states to get sushi at.

I have all the fancy sand papers and even fuji film pressure film... Too scared to try it on my 3930k.