This article is from the RCA SelectaVision VideoDisc FAQ, by firstname.lastname@example.org (Tom Howe) with numerous contributions by others.
but poorly in between. What causes this?
CED's are designed so the edge and center section are raised higher than
the grooves, so the grooves are not damaged when the player extracts the
disc from the caddy. But putting a lot of weight on the caddy pushes it
down so that the grooves are abraded by the inside wall of the caddy.
This usually happens when a bunch of CED's are transported in a flat
stack. The grooves at the beginning and end of play are protected,
because they are closest to the raised rim or center section. It is very
important when shipping CED's that they are stacked on edge instead of
flat, with the box clearly labeled FRAGILE and THIS SIDE UP on the
outside. I once received a box of CED's that the owner had stacked flat,
and several of the discs on the bottom of the stack were badly damaged
by the overlying weight rubbing the caddy against the grooves during