Last week on Broadway, the best way to boost box office was to close.

“Irena’s Vow” and “August: Osage County,” two of the four shows that shuttered Sunday, both saw sales spike in a flurry of last-minute biz.

“Irena’s Vow” ($337,100), which struggled to attract auds throughout the course of its Rialto lifespan, logged its best numbers yet by a wide margin, with the weekly total leaping by a whopping 73%.

Meanwhile, “August” ($414,600), which has seen sales diminish in recent months, jumped by 47%.

Also exiting the boards Sunday were nonprofit productions “The Philanthropist” ($296,284) and “Accent on Youth” ($163,039), both of which climbed, but by smaller increments.

Overall, Broadway cume rose, with total sales up about $600,000 to $21.5 million for 28 shows on the boards. Six shows, from “Wicked” ($1,606,120) to “Hair” ($1,131,458), held on to their memberships in the millionaires’ club.

Among the new tuners of the most recent season, “Next to Normal” ($480,535) and “Rock of Ages” ($655,962) both continued to build steam. “9 to 5” ($783,435) slid slightly, while “Shrek the Musical” ($957,694) essentially held steady.

Two play revivals still working to boost receipts, “The Norman Conquests” ($315,992) and “Mary Stuart” ($313,219), also were among the handful of shows to post minor declines.

Broadway attendance was up a bit to about 250,000. That’s off from the same week last year, which brought in more than 275,000 theatergoers, although that week there were seven more shows playing than there are now.

Although summer is traditionally a time of bounty along the Main Stem, legiters expect box office to slip during the coming frame thanks to the Fourth of July holiday, which usually prompts a drop in B.O.