28 Dash light intermittent operation

[Cliff Ramsdell]

Hi all,
Picked up a really nice plated dash for my car. Has the original oval speedometer and dash lamp. My problem is the lamp won’t stay on. It will come on when I turn it some but it’s off when either in or out.

What’s the best way to take the lamp apart to clean and service it since I’m sure after 90 plus years it could use some service.

Hook me up guys.

Thanks,
Cliff Ramsdell