This should be removed for cleaning and oiling every 5,000 miles approximately. It should not be taken apart, and in no circumstances should the wire wool element be unwound as it will be difficult to refit properly, resulting in unsatisfactory filtration.
Wash the entire air cleaner assembly in petrol until all accumulated dirt is removed. Dry out thoroughly by compressed air blown through the cleaner or use moderate heat to do so. Prepare it for further use by immersing in engine oil (Viscosity S.A.E.50). Allow all excess oil to drain off, wipe externally and refit to the machine.