After doing a PCR, the resulting DNA should be cleaned up to get rid of the primers, the enzymes and the various other reagents used in the PCR. This can also be used to remove small fragments of DNA from other sources (such as digestions).

We used Macherey-Nagel's "Nucleospin® Gel and PCR clean-up" kit. Its manual can be found here: [http://www.mn-net.com/Portals/8/attachments/Redakteure_Bio/Protocols/DNA%20clean-up/UM_PCRcleanup_Gelex_NSGelPCR.pdf Gel and PCR clean-up Manual]