Beginning in 1889, prerecorded wax cylinders were marketed. These have professionally made recordings of songs, instrumental music or humorous monologues in their grooves. At first, the only customers for them were proprietors of nickel-in-the-slot machines—the first jukeboxes—installed in arcades and taverns, but within a few years private owners of phonographs were increasingly buying them for home use. Each cylinder can easily be placed on and removed from the mandrel of the machine used to play them. Unlike later, shorter-playing high-speed cylinders, early cylinder recordings were usually cut at a speed of about 120 rpm and can play for as long as 3 minutes. They were made of a relatively soft wax formulation and would wear out after they were played a few dozen times. The buyer could then use a mechanism which left their surfaces shaved smooth so new recordings could be made on them.