Higgs Boson:

Hiring someone with a hand grinder to grind that paint off is going to be expensive and any grind wheel he uses is going to get all gummed up with paint quickly. Instead, just mail order a cheap hand grinder:



from Harbour Freight or wherever and fit it with a rotary wire brush, like this one:



or, if that seems kinda scary to you, consider buying a "cup" style rotary wire brush:

http://i.ebayimg.com/00/s/NTg5WDY0MA...d= 8800005007

and you'll tear that paint off your concrete real fast without harming the concrete.

Several important points:

1. Hand grinders spin at about 20 to 25 thousand rpm which is a LOT faster than bench grinders, and most rotary wire brushes in hardware stores and home centers are only meant for use on bench grinders. They will only be rated for about 6,000 rpm at the most. Go to any welding supply store and you'll find rotary wire brushes there rated for 25,000 RPM and more. Those are meant for use on hand grinders.

2. A wire brush spinning at 25,000 rpm WILL occasionally lose a wire, and those wires WILL go through your clothing and occasionally stick into your skin. You might have to stop work and pull the odd one out. But ALWAYS ALWAYS ALWAYS wear eye protection when using a rotary wire brush on a hand grinder. If you're using a regular wire brush and not the cup style, then ALWAYS wear leather work gloves with it as well just in case you inadvertantly touch the spinning brush or it throws a wire at your hand.

3. Normally, the safety guard on a hand grinder is meant to fit over and around a grinding disk, which is very much thinner than a bursh. It won't fit over a rotary wire brush because they're generally a lot wider then a grinding disk. So, you almost certainly will have to operate the hand grinder without the safety guard on it. That's a good reason for wearing leather gloves anyhow. I can't remember the last time I had the safety guard on my grinder because like most people, I use it without the safety guard. If you opt to buy a cup type rotary brush, it won't be dangerous at all because your hands won't be near the spinning wires.
But, since the safety guard will be off your hand grinder anyhow, try to get a rotary wire brush that screws onto the arbor of your hand grinder (like the two shown above) rather than just slips over the arbor and is held in place with the hardware that came with the hand grinder. Brushes that have a nut welded to them so that they screw on will be held further away from the hand grinder so that the brush is a bit further from your hands and well away from the grinder itself.
The standard arbor size used in North America on hand grinders is a 5/8 inch National Coarse threadm or 5/8 inch diameter by 11 threads per inch. Make sure any hand grinder you buy has that kind of arbor, and that any brush you buy will screw onto that kind of an arbor.

4. If you're concerned about inhaling lead dust, wear a dust mask and work only on windy days.