On Jan 1, 7:23*pm, "toolman946 via CraftKB.com" u40139@uwe wrote:
I have a black, hard Arkansas oil stone that's probably close to 100 years
old (handed down from grandpa). The surface isn't flat anymore and it has
some chips and dings from many years of service. It doesn't seem to cut very
well too, and I'm guessing the pores are filled with dirt and dross.

Natural stones from Arkansas are alumina or emery (alumina with
magnetite, so they're black), so a diamond hone will dress the
surface.
Don't do that until you've cleaned it, though. I'd start with hot
soapy
water, then rub vigorously with a good quality plastic eraser (in my
experience, this removes surface gum and glaze), work it against
a cheapo (dollar store) gray stone for a bit, and finish with a
few strokes against a diamond hone.

I wouldn't try to flatten it, and a few nicks don't hurt the
operation.
Remember, only if the nick is as big as your bevel will the blade
alter course going over it!

I use my natural stones with a little soapy water, and they don't seem
to
clog. Oil has never worked well for me.