Disclosed are compositions comprising, per litre of aqueous solution, from 30 to 350 g polyethylene glycol, from 3 to 20g of an ascorbic acid component comprising a mixture of ascorbic acid and one or more salts of ascorbic acid, and optionally one or more electrolytes selected from sodium chloride, potassium chloride, sodium hydrogen carbonate and one or more alkali metal or alkaline earth metal sulfates. Solutions and kits containing said components are also disclosed.
