I found an 1803, 1/2 cent and a 1785 or 6, NJ cent. Painstakingly cleaning with peroxide & cotton swabs. have revealed the date,1/200,&head outline on the 1803, and can only see the shield on the NJ cent. I have put over an hour into peroxide & swabbing looks like a lot more detail could be exposed. when do I stop? What do I need to do? do not want to ruin with sonic or vinegar/salt cleaning...