Bay Area consumers shook off any lingering eggnog hangover and slowly made their way back to the malls on Thursday to pick through the post-Christmas sales.

And there were plenty of sales, with bright signs plastered to storefronts that announced 70 percent off and stores beckoning customers with giveaways and even discounts at the gas pump.

Malls were open early -- some big-box stores at 5 a.m. -- and by late morning, Bay Area shopping centers were busy with shoppers looking for bargains.

"This is our Christmas Day. We get better deals the day after," said Mickey Peterson of Livermore, who arrived at Stoneridge Shopping Center in Pleasanton about 7 a.m. She had asked for money from her family to buy gifts for herself, she said.

Lukas Bienert, 7, of San Ramon, searches for an outfit for a new bear at the Build-a-Bear Workshop in Stoneridge Shopping Center on the day after Christmas
Lukas Bienert, 7, of San Ramon, searches for an outfit for a new bear at the Build-a-Bear Workshop in Stoneridge Shopping Center on the day after Christmas in Pleasanton, Calif., on Thursday, Dec. 26, 2013. This holiday shopping season was the shortest in more than a decade. (Anda Chu/Bay Area News Group) ( ANDA CHU )

Sisters Catherine and Emily Wolf of Campbell also waited for the after-Christmas sales to buy gifts for each other.

"It was kind of like Black Friday," Catherine Wolf said about the discounts.

With the prime shopping days of the year behind them, retailers are trying to make room for spring merchandise that will arrive after the New Year and squeeze the final dollars out of consumers before a brief and mostly lackluster holiday season comes to a close.

Stores hope the deep discounts will persuade consumers making returns or exchanges to make impulse purchases or buy an item still on their own Christmas wish list.

Judy Shimamura, who was shopping at Stoneridge early Thursday, said she had been eyeing some new clothes for work before Christmas, but held out. "It's marked down more now," she said. "I knew it would be."

Jason Alley of Pleasanton was at Best Buy on Stevens Creek Boulevard in San Jose looking for a new laptop for his wife.

"It's a necessity, and we thought we might get the best deals after Christmas," Alley said.

Although often overshadowed by Black Friday, the day after Christmas is one of the most critical of the year for retailers. Shoppers, many on vacation or home from school, use the day off to spend gift cards or cash from family and buy accessories for a new outfit or parts for an electronic gadget.

Pierre Bierre of Pleasanton emerged from a mobbed Apple (AAPL) store with a cable for his new Apple TV, a Christmas gift from his family. It would be his only purchase of the day, but he was giddy about it.

"I'm going to watch TV the rest of the day," he said.

Gift cards accounted for more than 20 percent of holiday spending, according to the International Council of Shopping Centers, and post-Christmas shoppers were eager to use them. Tess Sanchez, who has two children ages 11 and 16, said she gave gift cards to Barnes and Nobles and Target to let the kids pick out their own gifts.

"The older kids are very picky," she said.

Bill Tancer, general manager of global research for Experian Marketing Services, a consumer research and marketing firm, said holiday shoppers will continue buying into the New Year when they can find cheaper prices on big-ticket purchases like TVs and furniture.

Best Buy plans on replacing at least one-third of its store with the latest electronics soon after they are unveiled at the Consumer Electronics Show in January, said store general manager Rich Scharaga. The old models will go on clearance and the prices will drop steadily.

"At some point in time, we'll get people to buy it," Scharaga said.

This year, post-Christmas sales are perhaps more important than in previous years, because many stores lost sales due to the shorter holiday season, which was compressed to 26 days, the shortest in 11 years. In-store retail sales declined 3.1 percent the week before Christmas from the same period in 2012, according to ShopperTrack. In-store holiday spending is projected to be the lowest since 2008, according to the International Council of Shopping Centers.

Online sales, however, remained strong through Christmas Day. During the last shopping weekend before Christmas, Web sales jumped 37 percent from the year before, according to IBM Digital Analytics. And Christmas Day, online sales were up 16.5 percent over last year. Amazon announced on Thursday that 2013 was its best-ever season, and Amazon Prime had a record-breaking number of new customers.

The late surge of online shopping overwhelmed some e-commerce companies and delivery services, which failed to meet their own shipping deadlines, leaving some people without gifts to give on Christmas. United Parcel Service realized Tuesday that it wouldn't deliver some packages in time for Christmas, and FedEx was also scrambling on Thursday to deliver packages that should have been under the tree.

Guille Mota Meza of San Jose said in a note on Facebook that he ordered a Kindle Fire from QVC that was supposed to arrive by Christmas Eve.

"It never got here," he said. But he said Christmas will come this year, albeit a day late. He called QVC Thursday morning and got a refund on his shipping fees and a $25 credit.

"And I will be getting my Kindle today," he said.

Contact Heather Somerville at 510-208-6413. Follow her at Twitter.com/heathersomervil.