Manhattan Silver/White (drugs)
Jonathon Green's Cassell Dictionary of Slang (1998) has these entries:
Manhattan silver/white n. [1970s+][drugs] an imaginary brand of marijuana, silver/white because its seeds have grown in darkness, after being flushed away into the sewer system [cf. NEW YORK CITY SILVER].
New York City silver/white n. [1970s+][drugs] an imaginary brand of marijuana, silver/white because its seeds have grown in darkness, after being flushed away into the sewer system [cf. MANHATTAN SILVER].
Manhattan silver/white n. [1970s+][drugs] an imaginary brand of marijuana, silver/white because its seeds have grown in darkness, after being flushed away into the sewer system [cf. NEW YORK CITY SILVER].
New York City silver/white n. [1970s+][drugs] an imaginary brand of marijuana, silver/white because its seeds have grown in darkness, after being flushed away into the sewer system [cf. MANHATTAN SILVER].