Are you sure it was mould? VDS (vinyl deterioration syndrome aka 'pony cancer', which is nothing of the sort and isn't a terribly appropriate name for the condition) is not treatable by boiling or cleaning or any other method, it's entropy. You can't stop chemical bonds from deteriorating in an unstable substance such as most modern plastics, including vinyl. You can slow it down with proper storage conditions, but it never really halts completely.