non-contiguous file selection

[Jane Jordan (gmail)]

I need to select several files in a folder for deletion.  They are  
every other file.  Need to get rid of all of the .aiff files and save  
the .mp3 files.  I know I've done it before, but for the life f me, I  
can't find the instructions.  Can someone email me off-list with how  
to do it?

Jane