Would you like a bacon and cheese sandwich?

This obviously assumes they're a kosher jew.

Ask them what they're doing on Saturday, maybe see if they'll help you do some work. All depends on the situation though.

Otherwise, you could just use your jewdar.

"If i wanted to bake a huge amount of choc chip cookies, say, like, in the millions how many ovens would i need and how long would it take to bake those cookies..."

"Well i have a goy in armenia who has a faheeeeeeeeeeeeeeeeeeeeey now wait a minute...."

Talk about The Return

“Does this smell like zyklon to you?”

"So, what church do you go to?"

That should do it. It's a common question, shouldn't arouse any suspicion.

“I’m thinking of going on vacation after I get my vaccine. Maybe to Israel, have you ever been?”

"My mother, she's jewish,....."

"Sometimes these Goyim, you know"

Just start talking about how your ancestors in Ireland or Whales or some other European country had it hard in the pre industrial age and you will be immediately interrupted by mu six gorillion horse shit tales and other narcissistic ramblings.