Dahon not folding - how to (quickly) un-rust hinge?

[Pancho]

I'd planned to use my Dahon Sport TR for a multimodal trip to the Long Itch Convening tomorrow. I'd rescued it from "back of shed" status earlier in the week and thought I was good to go. But, today, I go to give it a quick fold - and find that it won't. The main hinge was rusted shut. Careful application of violence and 3-in-1 has made it foldable again - but only with use of much force, both arms and legs, and a great deal of general faff. Not what you want to be doing on a station platform.

Anything I can do to quickly rescue it? Or I'll be on the bus tomorrow.

VMT.

[DaveReading]

WD-40.

[rafletcher]

3-in-one penetrating oil, or better still PlusGas (from motoring stores).  Then repeated opening & closing and finally more plain 3-in-one.

[hatler]

^  ^  ^  That  ^  ^  ^

[Jurek]

Little movements first.
Until things naturally loosen up.

This is one of those multi-board posts.
Could comfortably be posted in Health & Fitness or NSFW....