Can you use a 0% interest credit card to pay down mortgage?

[Deadrick Colbert]

Can you use a 0% interest credit card to pay down a mortgage balance?

[Chris Mason]

Let's say you charge $20k onto a credit card that's maxed out at $20k, and as such you save 4% on that $20k for 18 months.

$20k*4%*1.5= $1200 saved. 

It took 18 months to save that $1200. That's $66.67 per month and you probably tanked your FICO score by maxing out the credit card.

You're on THIS website, and you can't think of a better way to generate/save $67 per month?