NOT TO PICK on bicyclists - God forbid! - but how can some riders board a SEPTA bus with a bike, then leave it behind when they depart?

It's a mystery not just to me, but also to SEPTA officials Christopher Valentin and Frederick Melhuish Jr., who supervise the lost-and-found for the Midvale depot, which runs 26 bus lines from South Philly to Doylestown.

SEPTA has eight lost-and-found locations, all using log books, not computers. About 2,000 items a year are turned in, from bicycles to (lots of) cellphones, canes, umbrellas, baby strollers (no babies, as yet), even a set of false teeth.

"Why somebody took their teeth out on the bus and sat it down next to them, I don't understand," says Melhuish, 51. "It surprises me that the operator actually picked them up and turned them in."

Operators who turn in lost stuff get to keep it if it's not claimed in 30 to 90 days, depending on its value. Laptops, jewelry and cash are held the longest, but most of what is turned in is "junk," says Melhuish, a 22-year SEPTA veteran.

Among the spicier found items are porn DVDs, says Valentin, 32, with the more-senior Melhuish recalling when it used to be "magazines and pictures of loved ones in compromising positions. Now it all goes on the Internet."

Valentin adds: "Lots of marijuana. I just happened to walk back and saw a Black & Decker vacuum, a blind man's cane, walkers," he says. Smaller lost-and-found items are kept in cardboard boxes in a locked closet.

If items have identifying information, clerks make an attempt to locate the owner and will call or mail a card, says Valentin.

"We look at the wallets for identification," says Melhuish. "If we find a phone, we call if they have 'home' or 'Mom' listed."

In stock right now, Valentin says, "We have a laptop, projector and a video camera. We can edit our own movies."

As for the left-behind bicycles, "some people have a theory that they're stolen and they let them get taken back to the depot and they'll come pick it up in a couple of weeks, but I've never seen any validity to that," says Melhuish.

"Folded-up shopping carts is another big item," says Valentin, with 13 years on the job. "All these groceries in a cart - you rolled it to the bus; you get off the bus; you're carrying the groceries." And you get off without the cart?

Canes, too. You were limping when you got on the bus, but got healed during the ride?

Most passengers either don't know they can call, or don't bother. The central number, 215-580-7800, directs callers to the right depot.

Most found items are junk, but that was not the case a couple of weeks ago when an operator turned in a purse containing $4,000 in cash, Valentin says. There was no ID, but there was a card of a Brooklyn insurance agent. SEPTA supervisor Dave Rogers took a shot, called and quizzed the agent.

Amazingly, the agent knew who owned purse. She was contacted and picked up her cash yesterday.

Operator Aaron Hurst, 51, was the SEPTA worker who found and turned in the money.

He had picked up a lady's purse from the floor of his bus and opened it. When he saw all the money, "it kind of made me nervous," he says, but he rejected any idea about pocketing it. "My parents taught me to be honest," he says.

That's a lost value for many people. It would be nice if they found it.

Email stubyko@phillynews.com or call 215-854-5977. See Stu on Facebook. For recent columns: