Photo by caroline.angelo.

Want to show your gratitude to the garbage collector who had to pick up the remnants of your last house party with a modest gift card? Yeah, don’t.

I’m not trying to be impolite — it’s just not kosher. Michael Neibauer at the Washington Business Journal got his hands on a memo from D.C. Chief Financial Officer Nat Gandhi, which reminds people that District employees are forbidden from accepting gratuities from pretty much anyone.

A donut every now and then, though, is totally okay:

“Gifts of food and/or beverages, even during holiday seasons and other celebratory occasions, are not acceptable if the giver has a business relationship of any kind with the D.C. Government,” the memo states. “Such offers, while well-intentioned, tend to give the impression of a special relationship between the giver and the government employee.”

The gratuity rules do not apply to an “insignificant item” like a “soft drink, coffee, donuts and other modest items of food and refreshments when not offered as part of a meal.” So, go ahead and ply your CFO contact with a Krispy Kreme and latte, or a Coke and a cookie. But that’s as far as it goes.

So, to summarize: a chocolate chip cookie from Ripple, okay; a twenty dollar bill, not okay. (Something tells me you’re going to get much better service after offering the former anyway.)