Seaside police Chief Robert Gross said Ryan Bensen, 40, and Erica Manley, 37, dined Thursday night at the Twisted Fish Steakhouse in Seaside and they paid their bill with a gift card, the (Portland) Oregonian reported Wednesday.
The couple handed their waitress an envelope marked with a question mark as a tip, Gross said.
The waitress examined the envelope's contents and called police when she determined it could be crystal meth, restaurant manager Steve Keszler said.
Keszler said the restaurant does not commonly have such incidents.
"We're not a little dive bar or hole in the wall. We're a classy place," he said.
Gross said Bensen and Manley were still at their table when police arrived at the eatery. Officers found searched Manley's purse and discovered 17 ounces of meth, Gross said.
"While I should be shocked and surprised, it's just another example of how dumb these users and dealers are," Gross said. "The whole thing almost made me chuckle."
Gross said police found a meth lab at the Holiday Inn Express room where the couple had been staying.
Benson was arrested on charges of with possession and manufacture of methamphetamine. Manley was charged with possessing, delivering and manufacturing meth.