CD Transport Maintenance

I have a Theta Basic II transport that I enjoyed very much. Recently it has developed a small squeek as the transport drawer opens and closes. I wanted to know if you can and should lubricate the drawer and if so with what? Also is there a safe and effetive way to clean the lens?
It is a great idea to lube the drawer but I can't say how.
The teeth do become very brittle. Mine broke all off unexpectedly and Theta replaced.

You can clean the lens with a fluffy Q-tip swab dipped in alcohol. Be careful though because the lens is suspended in a rubbery spider. If you press heavily on the lens it gets stuck too deeply in the spider and won't recognize CDs. Gently prying it out again seems to work OK. FWIW, cleaning my Data Basic II lens didn't help with skipping. Sending it back to Theta for some capacitors and a laser lube job solved that problem.
I used a light silicon lubricant on a squeeky Denon drawer, applied to the teeth and rail. It worked wonders.
from experience, dont mess with transports. its best to send them back to the manufacture or someone local that knows how to work on them. its cheaper and can give you less headaches. most lenses dont need to be cleaned. if its just the drawer call theta and ask them what to do. most of these manufactures are really good at helping you out.