Turn off the stove and exhaust fan. Remove the exhaust fan filter from the fan. The exhaust fan filter is located in the stove exhaust hood. The exhaust fan filter either slides out or has several tabs holding it in place, depending on the type. After removing the exhaust fan filter, the fan should be visible.
Put on the rubber gloves. Dampen a cotton rag with warm water. Add a small amount of CLR to the dampened rag. Wipe the fan with the rag and CLR.
Dampen another cotton rag with cold water. Wipe the fan with the damp rag until the CLR is removed. Rinse the rag with cold water again and repeat the process until there is no CLR on the stove fan. Allow the fan to dry then replace the exhaust fan filter.