Homeless they may be, but Kevin DeMello and Boris, aka “Moscow,” adhere to a strict set of rules when it comes to common courtesy and common sense.

They don’t keep pestering someone after they’ve given a donation.

They don’t ever “mistake kindness for weakness.”

Don’t prey upon others; don’t steal; and don’t give street people a bad name.

Use the buddy system; guard each other while the other sleeps.

“If you are alone, you might as well have a sign on you that says ‘victim,’” DeMello says.

When he was on the streets by himself, he said, he was robbed several times, losing his wallet on one occasion while sleeping and, another time, his jacket.

Boris does more than just watch his buddy’s back and share food, money and booze. He also reigns in DeMello’s boisterousness.

“What do you say to a woman with two black eyes?” DeMello asks Boris. “You don’t tell her anything. She has already been told twice.”

Boris frowned.

“That’s not funny,” he said. “I don’t believe in battering women.”

“Oh yeah, well you never met my wife,” DeMello counters, adding that she “really clocked me” before throwing him out. He said he was once a happily married member of the community, living in the Porter Square area.

Both are carpenters, and Boris is a jeweler/clock repairman who can “fix anything that tells time.”

They say they are unemployable because of their severe alcoholism, Hepatitis C and cirrhosis. “In Russia, drinking is a national pastime,” Boris says.

Boris says he came to America with his father in 1979, starting out in Detroit and drifting around for years before settling in Cambridge in 1998. His father died three years ago in Brighton, he says.

Both men have modest expectations in life.

He woke up that morning with a seizure from alcohol withdrawal, but Boris now produces a bottle of some type of alcohol, either gin or vodka, and takes enough to steady his nerves.

Sounding just like Gene Wilder in the movie “Blazing Saddles,” he holds up his shaking hand and explains that it is hard to be a carpenter when “this is the hand I hammer nails with.”

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