Polypropylene is thermoplastic and stands temperatures under boiling temperature of water. It is molded into tubs and parts for washers and dishwashers and other items; and made into fibers for carpets and upholstery, when the name "Olefin" is often used, as a trade name. It is not affected by most common alkalis and acids, but is damaged by solvents, boiling water, and citrus fruit rinds.
Avoid contact with boiling water, high heat, flame such as cigarettes, and abrasives. Wash in warm sudsy water. Never use scouring powder.