Patent ID: 8431516

Claim:
A cleaning solution comprises a. greater than 6% by weight of an alkyl diphosphonic acid of the basic structure: wherein R 1 and R 2 are either the same or different and select from the group consisting of hydrogen (H), hydroxide (OH), chloride (Cl), alkyl or aryl having between 1 to about 8 carbon atoms and alkyl or aryl amine; b. sulfamic acid; c. a buffering amount of one or more metal ion free basic compounds selected from the group consisting of hydroxylamine freebase, a hydroxylamine derivative, tetraalkylammonium hydroxide, TMAH pentahydrate, BTMAH (benzyltetramethylammonium hydroxide), TBAH, choline, THEMAH (Tris(2-hydroxyethyl)methylammonium hydroxide)), monoethanolamine, 2-(2-hydroxylethylamino)ethanol, 2-(2-aminoethoxy)ethanol, N,N,N-tris(2-hydroxyethyl)-ammonia, isopropanolamine, 3-amino-1-propanol, 2-amino-1-propanol, 2-(N-methylamino)ethanol, 2-(2-aminoethylamino)ethanol, tris(hydroxymethyl)aminoethane, or mixtures thereof; d. from 0% by weight and up to 5% by weight of a surfactant; and e. water.