how do you de-select songs from your library that you dont want as part of iTunes match?

i have over 36,000 songs in my Ttunes library. iTunes match only allows 25,000. there aer songs in my library that i dont need or want as part of iTunes match. How do you delesect songs/tracks so that they are not part of the total library for iTunes match? I want to still have the songs as part of my master library but not part of Itunes match so tht i can get in under the 25,000.