Abstract: A yarn (F) for car wash brushes includes and end portion (R) that is tapered down to a thin size smaller than 0.25 mm so that it is soft and does not retain dirt, whereby the cleaning effectiveness of the brushes made with this type of yarn remains unchanged over time and there are no risks of damaging the paint due to dirty ends. Moreover, it is possible to have yarns smaller than 1 mm made of polyester or nylon, that have greater cleaning effectiveness, are more delicate on the paint and last up to 5 times more with respect to conventionally used materials.