The San Diego County Fair’s lost and found area at Guest Services is holding 33 sets of keys. Photo by Chris Stone

Seen your car keys lately? How about your microwave oven?

Gail Thompson, the fair’s Guest Services supervisor, shows files of lost and found credit cards. Photo by Chris Stone

While you may have left the San Diego County Fair with good memories and a full stomach, you could have left something more valuable behind.

Many people are forgetting to fetch items from the plastic trays as they enter through security check, says Gail Tompkins, fair Guest Services supervisor. Jewelry is left in the bathrooms.

This week, the fair said its Lost & Found held a microwave, five pieces of luggage, three large strollers, six single baby shoes, a basketball, two walking canes, an umbrella, boxes of clothing and boxes of hats, 47 pair of glasses, 33 sets of keys and 63 credit cards.

More than a million people have attended the fair so far, according to spokeswoman Shawn Feisst.

In past years, items left behind included a set of dentures, an oxygen tank, crutches and a man’s birth certificate.

It’s best to retrieve belonging before the fair ends July 4, officials say. After that time, staff is significantly reduced, and it will be much more difficult to retrieve lost items.

Guest Services can be reached at 858-794-1124.

Here is how people can retrieve lost item without paying for parking or admission, according to the fair’s website:

After hearing from Guest Services that it may have an item, visitors should go to the main parking lot with $31 in cash. Entering the parking lot, they should explain to the attendant that they are picking up a lost item. The attendant will collect a refundable $13, and will be directed to a temporary lot.

Visitors should then go to the Will Call window to the left of the O’Brien (main) gate, and pay $18 for temporary admission and get a receipt.

After retrieving their lost item at Guest Services, visitors should immediately leave the fair to get their $18 back from Will Call and $13 parking fee from the attendant as they leave.

People have about an hour to complete the task if they want a refund of admission and parking fees.

Guest Services is under the grandstands on the eastern end.