A process for purifying (i) a hydrophilic organic solvent, (ii) a hydrolysable organic solvent, or (iii) a mixture of a hydrophilic organic solvent and a hydrolysable organic solvent by removing ionic contaminants from the hydrophilic organic solvent, from the hydrolysable organic solvent, or from the mixture of a hydrophilic and a hydrolysable organic solvent without generation of by-product impurities, the process including the steps of contacting the hydrophilic organic solvent, the hydrolysable organic solvent, or the mixture of hydrophilic and hydrolysable organic solvents with a mixed bed of ion exchange resin; wherein the mixed bed of ion exchange resin includes a mixture of: (a) a weak-acid cationic ion exchange resin and (b) a weak-base anionic ion exchange resin.

A method of maintaining a cooling system includes the steps of introducing an ion exchange resin into a cooling path, performing ion cleaning of a coolant in the cooling path with the ion exchange resin, and adding an additive to the cooling path after removing the ion exchange resin from the cooling path.