How do you denature DNA?

All you really need to do to denature DNA is to boil it for several minutes. That’s it. Boiling DNA will not destroy it. DNA is very stable, and can tolerate high temperatures for a long time. Furthermore, one of the key steps of the polymerase chain reaction (PCR) is boiling (to denature), prior to the cooling step which allows annealing of primers to the DNA. So, here’s your protocol. Put the DNA into a test tube or eppendorph, place in boiling water for 5 minutes, remove. Done.

Oh, I should have asked what you need to do with the denatured DNA. There are other methods that might be more suitable. Still, nothing is easier than boiling.