What are the differences between virgin propylene glycol and reclaimed/recycled propylene glycol?
Virgin propylene glycol has never been used previously. Some boiler manufacturers state in their warranties that antifreeze made with virgin propylene glycol is required or the warranty is voided.
Recycled propylene glycol is captured and cleaned after use (mainly for de-icing aircraft). It is then considered a lower grade of propylene glycol and may still contain other ingredients even after cleaning.
Hercules Cryo-Tek antifreeze is made only with virgin propylene glycol.