this method works well for me
A small number of cells were suspended in 20 ul of sterile distilled water.
Adding 20ul of absolute ethanol, incubated for 1min at room temperature.
200ul of a suspension of 5% chelex 100 (stirring) in water were added to
Voxtexed, boiled in a water bath for 8 min
immediately cooled on ice.
Centrifuged for 5 min
2 ul of the supernatant were directly used in a 25 ul PCR reaction