With the ball bearings in a container pour in a little degreaser.

Kerosene, Mineral Spirits, or WD-40 Degreasers(not regular WD-40) are all great products you can use. Do not use it on non metal parts. Petroleum-based degreaser can eat away plastic and rubber components.

Cleaning the oil off is simple. Put a lid on the container and shake it. When finished remove the balls from the container and set them on a microfiber cloth to try.

Degreasers can be harmful to skin. I recommend wearing rubber/latex gloves.

Wipe the inside of the metal block and end caps with a microfiber cloth. I use a pipe cleaner to clean the channel.