You should never "grab" the prop with a glow igniter attached. This is an accident waiting to happen. By saying "grab," you are implying to wrap ones fingers around the prop and give it turn. I don't care how slow you turn the prop, if the glow igniter is attached, and the plug is hot, the engine could fire and your hand would be history. I've even had an engine start without an ignitor attached. It was still hot from the previous run. It died while taxiing, and I was just going to give it a spin to make sure it hadn't seized up or anything. It started. Surprise! Good thing I hadn't grabbed the prop! The rest of the advice is ok, but grabbing the prop can result in the quick removal of digits!