Add 20 mL of the CH3COOH, dilute to 150 mL, and heat to bp ;add NH4OH(1+1) to distinct yellow of methyl red.Digest ca 10 min on hot plate.Filter by gravity through 9 cm paper,catching filtrate in 100 50mm lipped Pyrex crystallizing dish;wash beaker 3 times and paper 5 additional times with neutral 0.5N NH4CH3COO.