Complex sentence: "Uncle" Jim O'Neal founded the Rural Rhythm label in 1955 in Arcadia, California, by mail order, often with a generic white front sleeve with a stamped serial number in the upper right corner.
Split into simpler sentences: Uncle Jim O'Neal founded the Rural Rhythm label in 1955 in Arcadia, California. He sold via mail order, records were often produced with a generic white front sleeve with a stamped serial number in the upper right corner.