Wear goggles if your hitting a hammer with a hammer! I had a red hot spark hit me in the knee hitting 2 hammer faces and it broke the skin. Had a shard in the eye once, no fun for about 90 minutes, the time it took my wife to take me to the optometrist and get it extracted with a Q-tip. She rolled the Q-tip backwards while digging out the shard and it snagged and pulled it out. She said I was lucky there was enough to catch on the Q-tip without surgery.
