sparkle plenty, n. — Green’s Dictionary of Slang

sparkle plenty n.

[Sparkle Plenty, a character in the Dick Tracy comic strip by Chester Gould (1900–85)]

(drugs) amphetamine.

1969		R.R. Lingeman Drugs from A to Z (1970) 232: sparkle plenties [...] amphetamines.
1971		E.E. Landy Underground Dict. (1972).
1980		‘Gloss. of Drug Terms’ National Instit. Drug Abuse.
2001		ONDCP Street Terms 20: Sparkle plenty — Amphetamine.