How do you remove the cover on a PVC toilet flange?

How do you remove the temporary cover on a PVC toilet flange? Mine has a tab on top, but when I try to twist it off, it won't budge. Thanks.

The tab is to hold onto it while you smack it with a hammer to keep it from dropping into the drain. I usually take a flat screwdriver and start it breaking then lightly tap it with a hammer all the way around

Those test plates are still fused pretty good to the toilet flange, so you will need a few hard hits with a hammer to bash it free. Once you bash a hole into it, you can usually rip the rest off with a pair of pliers to be on the safe side; you have to be careful that you don't accidentally hit the flange portion with the hammer and crack it!