"Scentless Apprentice" most likely dates back to late 1992, and is rare among Nirvana songs in that all three members - singer/guitarist Kurt Cobain, drummer Dave Grohl and bassist Krist Novoselic - contributed to writing.
According to the 1993 Nirvana biography Come as You Are by Michael Azerrad, the song's main guitar riff was written by Grohl. Cobain was initially unimpressed with the riff, and admitted in the book…
Like most babies smell like butter
His smell smelled like no other
He was born scentless and senseless
He was born a scentless apprentice