The answer to 'vacuum greasy' is that a vacuum cleaner can struggle to effectively clean up grease or oily messes. Grease and oils can cling to surfaces and get stuck in the vacuum's internal components, reducing suction power and potentially causing damage over time.
Common causes of a vacuum struggling with grease include cooking spills, pet messes, and general dirt and grime build-up. Symptoms may include reduced suction, the vacuum overheating, or the hose or attachments becoming clogged. For minor grease issues, you may be able to clean the vacuum's filters and hoses, but for more significant build-up, it's best to call in a professional cleaning service to properly deep clean the vacuum.