so i noticed on my lg 18650s one of them had these black circles that i could see through the wrap. So I Removed the wrap and noticed some areas of the battery that had a black soot like substance on it mostly by the positive contact. nothing else seems wrong with the battery and has been working fine. I scrapped off the substance with my nail and re wrapped them but am worried that maybe it is not safe to use and wanted to ask you guys before i do so to see what you more educated vapers think it is and if it is normal or not. also the white insulator on positive contact had little black stains from the soot.