You'll spend more on stuff to spray in it than just buying a new FW. If you do decide to take it apart, then do it in something that will catch all the little ball bearings and stuff that is inside.

You've been around here long enough to know that eventually someone will have given you this link and you've already looked at it, right?
https://www.sheldonbrown.com/freewheels.html

I thought I had a 6 speed Suntour Perfect sitting on the shelf taking up space but I just checked and it's only a 5 speed..