Hong Kong (CNN Business) Pro-democracy protesters are preparing to take to the streets of Hong Kong this weekend, and they're calling on supporters to withdraw their salaries from bank machines and convert their cash to US dollars.

The goal, for some protesters, is to make banks run out of money and pressure the Hong Kong dollar's fixed exchange rate as a way of leaning on the government. But the plan stands very little chance of success.

The strategy is one of several aimed at disrupting key businesses in Asia's premier financial hub. Hong Kong is facing a major political crisis. Sparked by opposition to a controversial extradition bill, the movement has since expanded to include calls for more democracy in the city and an independent inquiry into the use of force by police.

Mass demonstrations in recent weeks have shut down major lines on the city's subway system, temporarily crippled the international airport and hobbled business at hotels and restaurants.

Hurting the city's currency, though, will be much more difficult.

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