Don't worry about getting stung, if anything, you might get a little skin irritation.
Also, one of the main reasons for getting rid of them is that they spread very quickly, and pretty soon you have a tank full of Aptasia, that sting your fish and coral.
Inject any that you see. The "monster" may take a couple tries!
Peppermint shrimp are a good natural predator of them, but they can be hit or miss. I had 4 or 5, and my 2 peppermints cleaned them up in a few days time. They usually only work on small-medium ones, though. The shrimp are a good way to stay clear of them, especially when introducing new live rock. Any that spring up, the shrimp find them, and take care of them before they can be a problem.
Best of luck Arabella.