You can polish the (metal) shaft pins in blocks, as well as the holes in sheaves, with some very fine grit, wet-dry sand paper, & most any type of lubricant.
My brother gave me some funny
looks once, when next to my kitchen sink was; a pile of blocks, some 3m green abrasive pads, wet-dry sandpaper, & a bottle of machine oil, & lots of small bins & jars with lids (to keep the small pieces from "escaping", aka getting lost).
The 3M pads were to get off the big pieces of grime, & to clean up some individual (stainless steel) roller bearings, in a sink full of soapy water.
And the oil & wet-dry sandpaper, was for the bigger bits (as described above), after i'd cleaned them in the same manner as the roller bearings.
PS: When I say fine sandpaper, think 400-600 grit & smoother. Also, blocks that are made entirely out of metal are "dish washer safe".