FAQ: Can DNA be blunted using Exonuclease VIII, truncated?

No. Use DNA Polymerase I, Large (Klenow) Fragment (NEB #M0210) to fill in 5´ overhangs (also called 3´ recessed ends) and chew back 3´ overhangs or use Mung Bean Nuclease (NEB #M0250) to chew back 3´ or 5´ overhangs. Note: 3´ overhangs cannot be filled in.