It is recommended that discs be cleaned before—and after—each playback, carbon-fibre brushes are quite effective. Records should be cleaned in a circular motion, in the direction of the grooves. Distilled water (not tap water as it will leave behind mineral deposits) and a soft, lint-free cloth is a common method of cleaning. Another method is to clean the LP on the turntable with a disc cleaning brush (the Discwasher system is frequently recommended by the audio press). A simple "cleaning bath" device called the Spin Clean gives good results, and there are also vacuum machines on the market such as the Nitty Gritty, Keith Monks, Clearaudio, and VPI, which are recommended for more a thorough cleaning. In recent years, ultrasonic cleaning machines from manufacturers such as Klaudio (Korea) and Audio Desk Systeme (Germany) have also been used with great success. The effectiveness of the ultrasonic machines coupled with their premium price tags (both $4,000 US in January 2015) has opened the door for companies to offer professional ultrasonic cleaning at an affordable cost of just a few dollars per record. Though in the past, using alcohol on vinyl LPs was considered safe, experts now caution against it unless absolutely necessary, as alcohol threatens the loss of the plasticizer or stabilizer. As vinyl is often prone to electrostatic charges that cause dust and debris to be attracted to its surface, anti-static products can be used if needed.