<VV> Cleaning Concrete (clarification)

[Jim Simpson]

Oil and transmission fluids are both organic compounds that don't mix or
dissolve in water.  Given that they've had time to soak into the concrete,
there are a couple of approaches you might try.

First, use a organic solvent -- paint thinner, brake clean, turpentine or a
host of others (including very flammable things like gasoline) to dissolve
it.  Then you need something to absorb the dissolved material -- almost
anything including cat litter, "oil sorb", paper towels, etc.  I'd suggest
something powdery like cat litter that you can "grind" into the surface to
try to absorb the dissolved material.  You might have to try several times.

Second, try a strong soap.  Tide, Dawn dish washing liquid and similar
materials act to make organic materials (oils and greases) dissolve in
water.  I'd do this as a second course of action after the organic solvents.

Muriatic acid (hydrochloric acid) might help, but it's primary action is to
etch the surface of the concrete.  In so far as I know, it really won't do
anything directly on the oil and transmission fluid.  Instead, it removes
the top layer of the concrete so if the stain is in that layer, it will
come off with it.

But if your goal is to make the surface ready for an epoxy paint, muriatic
acid will give a good etched surface that the epoxy "should" adhere to well.

Jim Simpson
Group Corvair