That happens to me all the time with songs I was never particularly drawn to. Lately CSN's "Southern Cross' has been my bane.
The supposed cure is to sing the whole thing start to finish at one go, quite loudly. It is the interruption and incompleteness which sticks the song in the brain (as in the last song on the radio before work). Alas, I can claim only about a 50% success with this method.
Better than nothing.
Fortunately as I get older and certainly with my ailments I suffer with CRS.
Cain't Remember shit.
Now ... would you repeat the question?
To drive unwanted music out of my head, I turn to "Electric Aunt Jemima", which is part one of Frank Zappa's immortal Pancake Cycle.
None of the corrosive scheissmusik by which we are surrounded can stand up to that.
I call it the Idiot Radio station and it plays stuff all day long. Songs from the fifties that my mother listened to on the radio. Stuff from my youth, it goes on. It brings up stuff I couldn't possibly have consciously thought of. Yesterday the words and music to Sad Eyed Lady of the Lowlands slowly reeled themselves out over and over. I just have to swing with it.
"How much is that doggie in the window..."
Damn, I remember the jingle when I was a kid:
"Get Vick's medicated cough drops.
They'll soothe the tickle away.
Get Vick's medicated cough drops.
Pick up a pack or two today!"
It was everywhere on TV and radio. Ubiquitous. No escape from it at all.
The friggin' thing used to haunt me all the way through college. Could not get it out of my head.
I *DESPISED* that ad campaign.
(and yes, I made it a point to never, ever, buy anything with the Vick's name on it. My first act of rebellion against a corporation.)