"It may well be safer to rent a 5000 psi pressure sprayer and simply blast the paint away. Be careful though, I've seen one cut a hole in asphalt so don't point the sprayer at anything that don't need spraying. Especially at people. Going over all the concrete will make everything look more consistent."

Already done it! That's why I said 'partly' green... some of the paint came up, but not all. We did it with the 1 degree nozzle, not sure of the psi. It was a rental from Home Depot.

Thanks for all the info. I will talk to somebody at the store when I buy and will certainly be careful. The potassium dichromate is probably pretty much the same when it comes to safety, and I have the neccessary gloves, safety glasses, and respirator. Should be fun :roll: