On woodrail machines, a small amount of candle wax in the glass grooves on
the rails frees up the glass and it slides in and out easily again. It also
gets rid of that gosh awful screeching noise when you move the glass!
On machines with plastic inserts put 409 cleaner on a rag and move it up and
down the guides. Keep doing this over and over with a clean part of the rag
until the rag comes out clean. Next, wax the whole playfield glass with a
good car wax. Now your glass will slide out very easily, and you won't have
to run for the Windex to get fingerprints off. They will wipe off easily
with a clean towel.