I recently watched Dave Jone's soldering videos for reeducation and, while I don't remember which of the 3 videos it was and I don't have time to watch them again for an exact quote, I'm 90% sure he says somewhere in there that you can't use lead free solder with ordinary tips, and you can't use lead free tips with ordinary solder. Is that correct? I just bought a new soldering iron and then found out that all the tips available for it are "Lead Free Style" - nothing else is available. Can I, or can I not, use these lead free tips with lead solder?