That depends.

Buy the "clean"-labeled song. Though some songs may say "explicit" next to them, though.

also note, however, that some of the labels are overlooked. I recently bought a metallica st. anger album, and i know for a fact it has language, but there was no label on it.

Then again, i've bought a "clean-labeled" album, that cursed.

so just be careful, it is usually correct, but sometimes not.