For the last few years, the Petaluma group Los Gu’achis has performed on the Saturday before Christmas on the sidewalk in front of Copperfield’s Books on Kentucky Street and donated its tips (usually more than $100) to a local nonprofit.

In past years, recipients have been the Cinnabar Theater and the Committee on the Shelterless (COTS).

This year the group will be playing Saturday, Dec. 20, from 11 a.m. to 1 p.m. and donating the money they collect to the Petaluma People Services Center to be used to tune their badly out-of-tune piano at the Adult Day Care Center on Howard Street, where Los Gu’achis and other volunteer musicians play regularly to entertain the seniors.

Los Gu’achis play music of Mexico, the Southwest and Early California. Members of the group are Barbara Arhon (violin), Chris Samson (rhythm guitar), Steve Della Maggiora (accordion and lead guitar), Stephen Tamborski (mandolin) and Tracy Grisman (bass). For more information about the band, visit losguachis.com.