Problem at the yellow mine digger

[marzy]

HINT:
It is is the lid on the gas can (not the machine) that has rusted. See if you got something that can help you to get it off.

This really confused me too; I ran around the complex for over an hour looking for something else to open the machine. In the end I had to look up a guide to work it out

I know it's a puzzle game but this could have been much clearer! Just thought I'd let you know, incase you wanted to stop other players getting frustrated!