I have never owned a table with telescoping rods; but when buying a table for home I did a lot of research. I remember reading where these types can build up "gunk" inbetween the rods... and possibly rust. The suggested occasional maintenance was to unslide the inner & outer rods from each other and clean them well. Someone had a brush (the diameter of the outer rods I.D.) with a 2 foot wire handle, and it was run in through the outer rods cavity.
I looked for a link and can not find it anymore.