Jim hall & Michel Petrucciani duet play My Funny Valentine

http://au.youtube.com/watch?v=PKDEzOA4wdQ

Thinking pairs of duplicates is a worry....
If you have duplicates A, B and C and matches are presented in pairs, it is possible to get this:
Match A B ..... delete A
other matches .....
Match B C ..... delete B
other matches ....
Match C A ..... delete C
End result = no duplicates, but no single copy either.

If these pairings are seperated by several other matches it's too easy to lose track of what you're doing. To my mind much better to see a list with, for example, check boxes, with all matching duplicates grouped together