john hamilton wrote:
After reading our newspapers we end up with an oily dirt on our hands, but
not after reading the magazine supplements that come inside the newspapers
or the television guide magazines.

The "oily dirt" is ink.

Magazine pages use a different kind of paper to newspapers. This paper
is coated during manufacture and the coating affects the way ink
interacts with the paper. Also, some magazine pages are (further) coated
after printing. It is these coatings which make magazines "glossy".

The coatings act as a barrier stopping the ink from rubbing off on your
hands.

The gentry would (and some probably still do - see episodes of Jeeves
and Wooster) get their butler or valet to iron the newspaper, which has
the effect of fixing the ink and (somewhat) preventing rub-off.