PCR Tricks: How to solve the PCR contamination problem?

In a transgenic research, PCR confirmation of the transgenic events is a must to screen them from the non-transgenic events. The positive control we keep is generally the isolated engineered vector plasmid containing the transgene. A common problem that occurs with most of the beginners in the lab is after keeping a PCR they get positive in all the samples along with positive, negative and blank. This mostly happens due to handling error i.e. In anyway you have ended up adulterating any one or more than one of your components with the template from the positive control vial or from any positive sample. This mostly goes undetected while keeping a PCR reaction and additionally a PCR reaction is really very sensitive.The best method to avoid this kind of problem is; divide your PCR components into 3 sets. One set will be exclusively used for keeping only positive control. Keep that set separately. Use the 2nd set to screen the samples and use the 3rd set to keep Blank and Negative control. Also note that when you are in doubt that the micro-pipette other than the tip portion has touched the wall of the vial; before using it for another component please wipe it once with 70% alcohol and use it after drying.