Recycled tons of bags are used to sort and clean waste bags. To remove any harmful contaminants, these materials are then chopped into sheets and transferred to the extruder. The sheet is melted at a high temperature. Eventually, the sheets condense into small polypropylene particles. At this stage of the bulk plastic bag recycling process, unused polypropylene is often added to make the recycled material stronger. The resulting material can be reused to make bags from ice.