Exonuclease I can be used with Lambda Exonuclease (NEB# M0262) to clean up plasmid preps. Exonuclease III (NEB# M0206) and T7 Exonuclease (NEB# M0263) will also work, but will damage nicked plasmids.
Although Exonuclease I can be used, we recommend using Exonuclease V (RecBCD) (NEB #M0345) to remove chromosomal DNA after plasmid prep (see our Application Note: Using Exonuclease V (RecBCD) to Eliminate Residual Genomic DNA When Purifying Low Copy Plasmids with the Monarch® Plasmid Miniprep Kit.
