the usual leakage is intended to lubricate the axle bearings on the way out..

By using grease on the axle bearings , it is retaining the lube oil, a bit more .

STP oil treatment adds some cling ..

some use chainsaw bar oil , which has sticky properties .

Like I say Phil Tenacious does well, is sticky, and the container makes squirting it in
the hollow axle end simple..

If you Dont have an old long nozzle oil can, getting to that oil cap in the hub shell is a challenge..

Those are estate sale or period collector Items, them selves by now..