Hi PCC

No need to remove the left knob on a Silent-Super. Here's what you do:

1, Swing the top carriage back (the one with the paper support) and lift the paper bale.
2, Pull the line finder knob to the out position on the left platen knob.
3, Slide the carriage all the way to the right. (use the M-R key if needed to go past the margin)
4, Look just in front of the right hand end of the platen and you'll see a tiny lever. Push this lever back and lift the right platen knob up and backwards at a 45º angle until the platen will clear the end of the carriage. Now gently pull the platen to the right and it should just lift out.

Hope this points you in the right direction,

Sky

Interesting.  I didn't have it all the way to the right when I tried before.  When I was lifting the platen out with the carriage centered it felt like something on the left side was holding on to it and assumed it was the left knob.

The paper bail rollers can be washed with something like window cleaner containing ammonia, that will remove a lot of the ink which may make them shiny and slippery. You can treat them with rubber rejuvenator, but you have to get them off the bail because that stuff will mess your paint up. If you want to replace them, you can do so with some automotive fuel hose, sticking them on a dowel in a drill chuck, and sanding them smooth. 
As for the paper tray feed rollers, move your carriage all the way to the right.
Set your machine so it is resting with the back/carriage side on a table (not completely upside down.)
Look at the bottom of the carriage about 1- 2 inches inboard from the right of the carriage.
While looking at the bottom of the carriage, take a hand and gently move the paper tray. You should see a screw moving with it. 
Unscrew that screw.
Curse a bit because you dropped it either into the carriage or onto the floor.
Retrieve the screw.
Set the typewriter upright and lift the paper tray out. It may have to kind of be worked out since it sits on and in the mechanism which sets tension against the platen.
The feed rollers are just held in with little hooks of aluminum and will easily pop out.
If the paper tray doesn't come out, there may be a corresponding additional screw holding it in to the carriage over on the left side. I've never seen this, but all three of my Super 5 SCs had a hole in the base of the carriage and a tapped spot for a machine screw in the base of the paper tray.
Have fun.
Phil Forrest