Oiling screws and pivot points

[Roger]

For screws on the adjustable gap receiver and on the 4th valve latch, is there a suitable oil or lubricant that can be used to keep these easy to turn? Over time they seem to "lock up" and could use some periodic lubrication. What's recommended that won't harm the finish of the instrument?

[davewerden]

I use the thicker key oil from Hetmann.

[Roger]

Thank you.