clean oil stone maybe Charnley

[Vpk]

Hello,
I have bought at a flea market in U.K this stone...

I think it is a Charnley but i'm not sure... confirm at this regard will be appreciated...it is very smooth and hard...
The stone was having strong kerosene smell..at home i washed it with very hot water and soap for dishes...now it absorbs water and seems to be cleaned...but still i have doubts about real color of this stone...maybe is required a more aggressive cleansing treatement before lapping? If so what can i do?