My husband just replaced a large portion of the plumbing in our house and after finishing realized in horror that the solder he used, and just bought from Home Depot, contains lead. He wants to totally redo all the plumbing by removing the copper pipes. What is the best approach here? Can the solder be effectively removed from the copper pipes or do you need to cut off all pieces that were in contact with the lead solder?

I suspect he bought 60/40 solder. 50/50 was used in the old days. I'd also be worried about the strength of the joint if he used 60/40. Lead fittings were used for years. Concentrate on the hot water lines first.

Lead solder is impossible to remove.

Start cutting and purchasing new fittings and lots of repair couplings.

What solder did he use? 95/5 is the requirement for drinking water lines. That's 95% tin and 5% lead.

It's a toss up between heating and pulling every thing apart and cutting out all the joints. If he pulls everything apart, wipe the pipe with a wet cloth while still hot and toss the fittings. Sand the pipe and remake the joints.

As said above, lead solder cannot be removed. He will have to redo every joint - meaning, cut out old fittings and solder on new ones. Sorry...