I agree with Craige, a 64-bit Windows box with a minimum of 16 GB of physical RAM, would be necessary to successfullyl open a 6GB SAS data set in JMP.
Have you considered doing the cleaning in SAS, say with some DATA step code? JMP does have some great data cleaning tools, don't get me wrong, but having enough memory to open the data sets successfully is just the first problem. It doesn't guarantee a pleasant experience in JMP working with such large tables.
Is the machine that has SAS installed a server, allowing you to connect to it remotely? JMP has good tools for connecting to remote SAS servers - File > SAS > Server Connections is the place to start. You'd need to know the machine name and port number of the SAS server (or, if you also have a SAS Metadata Server, that makes connecting even easier).