How to remove old A/C piping in my house?
If the refrigerant has been removed, this is an easy task.  I'd assume the refrigerant was recovered when the old condensing unit was removed, but I only know what you've told us.

If there's no refrigerant in the lines, simply cut them out any way you like. Take the copper to the local scrap yard, and you can pay yourself for the work.

If the refrigerant is still in the lines, you'll have to have it recovered by an HVAC technician.