The use of an oil skimmer in the machine shop setting holds many benefits. Removing the oil from a machine coolant tank will initiate some esthetic benefits such as cutting down on the amount of smoke generated from the cutting tool coming into contact with oil laden coolant. 
Posts about Coolant Skimmers:
Rescue Your Coolant with Abanaki’s Oil Boss Coolant Skimmer | Abanaki
Coolant skimmers typically don’t come attached to CNC machines when they are newly bought. This is because nobody wants to admit that the brand-new machine is eventually going to leak oil into the coolant. This looks good on paper, but there is a reason why so many coolant skimmers are bought annually. CNC machines are bound to have at least a small amount of oil leaking into the coolant at some point. The skimmer will remove this oil from the top of the coolant for disposal. Without some type of coolant skimmer, the coolant life will be dramatically decreased. These small coolant skimmers will save you money throughout the operational life of your CNC machine.
Are Oil Skimmers in your Machine Shop? | Abanaki
Tramp oil got you down? Is your product quality being affected by floating oil? Have you asked yourself how you remove oil from water effectively and efficiently?