1. For each PCR reaction (50 µL) prepare a 1.5mL microcentrifuge tube containing the following: 
       - 5 µL of 3M sodium acetate (NaOAc), pH 4.6 
       - 100 µL of 95% ethanol (EtOH) 
2. Pipet the entire contents of each PCR reaction into a tube of sodium acetate/ethanol mixture. Mix throughly. 
3. Vortex the tubes and leave at -20^oC  for 30 to 40 min to precipitate the PCR products.       
4. Spin the tubes in a microcentrifuge for 20 minutes at maximum speed. 
5. Carefully aspirate the supernatant with a yellow pipette tip and discard. 
6. Rinse the pellet with 300µL of 70% ethanol. 
7. Vortex briefly. 
8. Spin for 5 minutes in a microcentrifuge at maximum speed. Again, carefully aspirate or decant the supernatant and discard. The pellet does not stick very well to the wall of the tube so be careful not to lose it! 
9. Dry the pellet in a vacuum centrifuge for 3 minutes or until dry. Do not over-dry. Resuspend in 50 µL of sterile water.