Medical marijuana shops are about to get a lot greener. As of Friday, there are no banks in the state that will openly work with dispensaries, forcing some shops to go cash only.

"We're not going to cut a hole in our mattress and keep thousands of dollars of cash in (there)," said Brandy Bowen, owner of Natural Remedies MMJ in Colorado Springs. "It's going to be difficult, and we're still not sure what we're going to do."

On Saturday, Bowen hung a hand-written sign near her register that said, "Cash Only." She's worried the new policy will make her shop, and others like it, even more of a target for thieves. Bowen has already had to beef up her security after her shop was burglarized twice in the last three weeks.

She said the dispensary will find a way to keep large amounts of cash out of the shop, but she worries what the perception will with criminals.

"My biggest concern is the safety of my patients and my employees as they stand in here with people thinking there's a ton of cash on site," said Bowen.

Bowen had an account with Colorado Springs State Bank, the last bank in the state that would openly work with dispensaries. That is, until Friday when it officially closed down medical marijuana accounts.

Dispensary owner Lono Ho'ala said his bank told him it had been pressured by the federal government to stop working with him.

"My banker told me they threatened him that he would be held as a co-conspirator in a felonious crime of conspiracy to distribute illegal drugs if his bank continued to work with me," said Ho'ala.

He pointed out that the government may not benefit from a group of profitable businesses that deal only in cash, especially when it comes to auditing.

"Now it's untraceable and what good does that do the government?" Ho'ala said.

He said his bank is one of the few that continue to quietly work with dispensaries. Even some of the shops with banks have found that their credit card processing services have recently been shut off.