ss DNA purification

[Sarven Sabunciyan]

Dear Netters!

Does anyone out there have a method for isolationg ss M13 phage DNA on a
cesium chloride gradient instead of a potassium iodide gradient?  What I
am doing is in vivo excision from a Lambda ZapII library but the ss DNA I
isolate has a huge contamination of ds DNA (concluded from S1 nuclease
digestion).  Any help is appreciated.  Thanks in advance.

Sarven