At my shop we use a product called "Greasweep". It is now no longer allowed here in California, luckly we still have a dozen bags hidden, but might still be available in other states. It is made from rice hull ashes with a bleaching agent. We first mop the mess with good old fashioned paint thinner and then sweep the Greasweep over to soak up the thinner. After about 10 minutes the area looks like clean white concrete again. The Greasweep can then be saved and used over and over untill it just won't dry any more. The thinner evaporates from the Greasweep so it will dry more messes up.