Use
rosin: A hard natural resin obtainedfrom pine tree oil and the wastesfrom processing wood pulp. It maybe colourless, yellow, brown, or black. It is used as a flotation agent,solder flux, sizing compound, and inlacquers and plasticizers. It is alsoused to provide ‘grip’ to violinists’bows (when it may be calledcolophony) and dancers’ and boxers’shoes.