[header] How to hold a door open with a coin [title] Grab a coin. [step] Canadian/us quarter or 20/50 euro cents work well. Avoid using small coins like pennies or dimes as they do not have enough surface area to hold the door open. 
You may need more than one coin if you're unable to jam the door open with a single coin. [substeps] If you're in another country like australia or south korea, use the largest and thickest coin possible.