Nail polish remover or acetone from the hardware store, a wire brush and rags will work. Apply, scrub, blot, and then repeat as many times as necessary. Work in small circles ina small area and work quickly. You don't want to spread it around more than necessary by pouring the acetone all over the place and spreading the now liquid nail polish further on the cement. This should get rid of much of it.
The little acetone that's left should not be a huge concern if you flush with a bunch of water.

Thanks, Rosa...
It sounds workable. Now I have to find a time to do it when my husband doesn't catch on. L.

pressure washer would work too