When spring returns, mallard ducks are a common sight on the water. In any season, you can find them in duck decoy collections and auctions. (Many were made) by the Mason Decoy Factory of Detroit, which operated from 1896 to 1924 and is still celebrated by decoy collectors today.

Founder William James Mason had been making decoys by hand for years when he started his company. When he died in 1905, the company passed to his son Herbert, who used his business skills to expand the operation.

One of Herbert’s innovations was the introduction of the inexpensive Standard grade of decoys. Before that, the company had made only two grades: the highest quality Premier and the slightly less detailed, less expensive Challenger. The decoy pictured here is Challenger grade.

All grades of Mason decoys are sought by collectors today. Because the company produced so many decoys — calling itself the “Largest Manufacturers Of High Grade Decoys In The World!” — they are some of the most common at auctions. But, like the ducks they emulate, being a common sight doesn’t make them less valuable.

Q: My father sold auto parts and accessories from the 1960s through the ’80s and accumulated a significant amount of automobilia including decals. Ideally, they were to be distributed to customers, but my father collected them himself. I’ve seen STP 4 3/4-inch’ oval singles for $2 to $5. How rare are sealed packs of 50 and 100 and what would they be worth?

A: STP, initially standing for Scientifically Tested Petroleum, started selling its oil treatment in 1954. Its popularity exploded in the 1960s, thanks to strong marketing and its association with racing. In addition to its tie-in with racing, STP was popular because it marketed itself as a product that could significantly reduce engine wear by providing an extra layer of lubrication between moving parts, thanks to its high-viscosity formula containing zinc anti-wear agents (ZDDP), which helped fight metal-to-metal friction, particularly in older engines; this was perceived as a way to extend engine life and improve performance, especially for drivers who drove in demanding conditions. Oval decals and, later, stickers with the STP logo were favorite merchandise. We occasionally see unopened packs for sale online, where they sell for about $100 to $150. You have something of value to many automotive collectors.

Q: I have two antique firearms that I would like to have valued. One is an antique rifle. Its markings are “1873 Torino.” The other is a shotgun marked “1879 Piepee.” Of course, these firearms are no longer usable. They have been used as an interesting display where my husband (now deceased) mounted them on a brick wall above the fireplace, where they got a lot of attention from any workmen in my home. There are a couple of people who are interested in purchasing them, but I have no idea of what they are worth. Can you help me with that, or tell me where I can get this information?

A: If you intend to sell your antique firearms, the first step is to check your local and state laws. Laws about selling firearms, even antiques, can be very strict. The gun marked “1873 Torino” was probably made at the Turin arsenal in Italy in 1873. Many guns made there were later modified for use in World War I. “Piepee” may be “Pieper,” for Henri Peiper, a Belgian company that made guns from the late 1800s to early 1900s. The 1879 reference on your shotgun may be the year the gun was made or the year its design was patented. We suggest you contact a local gun dealer and tell them what you have and that you would like to sell your guns. A dealer who specializes in antique firearms can help evaluate yours. To find a reputable dealer, check reviews and ask for references. You could also contact an auction house; there are many that hold firearms auctions and provide appraisals. Military Trader magazine (militarytrader.com), owned by the same company as Kovels Antique Trader, may have more information. Your situation is a good reminder to all readers to discuss with their spouse and loved ones the value and significance of all prized collections while still alive, providing supporting paperwork if possible. It is far easier to determine what to do with an item while we are alive, rather than leaving it up to a loved one to deal with it after we’re gone.

TIP: Do not store papers near sunlight, heaters, radiators, furnaces, stoves, lamps, television sets or any other heat-producing device.

EDITOR’S NOTE: Kovels answers readers’ questions sent to the column. Send a letter with one question describing the size, material (glass, pottery) and what you know about the item. Include only two pictures, the object and a closeup of any marks or damage. Be sure your name and return address are included. By sending a question, you give full permission for use in any Kovel product. Names, addresses or email addresses will not be published. We do not guarantee the return of photographs, but if a stamped envelope is included, we will try. Questions that are answered will appear in Kovels Publications. Write to Kovels, (Name of this newspaper), King Features Syndicate, 628 Virginia Dr., Orlando, FL 32803 or email us at collectorsgallery@kovels.com.

CURRENT PRICES

Current prices are recorded from antiques shows, flea markets, sales and auctions throughout the United States. Prices vary in different locations because of local economic conditions.

Castor set, six bottles, cut glass, stoppers, silver plate frame, center handle, pierced crest, bell, etched flower skirt, pedestal base, 18 inches, $60.

Purse, mesh, art deco style, black and white chevrons, fringe, metal and enamel frame and chain, black and white, satin lining, interior pocket, 6 x 5 inches, $70.

Barometer, thermometer, McAllister & Bros., mahogany case, banjo shape, C scroll trim, Phila., early 1800s, 39 inches, $90.

Toy, boat, ocean liner, red and white, two stacks, lithograph deck, painted hull, tin, propeller, windup, Bing, Germany, c. 1920, 7 inches, $95. Furniture, chair, midcentury modern, maple, split barrel back, upholstered back and seat, arms, marked, Italy, 29 1/2 x 26 inches, three pieces, $160.

Advertising, bin, McLaughlin’s Coffee, No. 99, dome top, multicolor graphics, coffee cup, leafy branch with berries, red trim, tin, 22 1/2 x 18 inches, $235.

Majolica, umbrella stand, turquoise blue ground, two birds, storks, raised leg, fish in beak, cattails, brown trim, 1880s, 21 inches, $750.

Cut glass, lamp, mushroom shape shade, peaked top, hanging prisms, baluster base, spread foot, electric, 26 inches, $840.

Silver-Asian, tureen, dome lid, elephant finial, raised trunk, rupee coin, relief figures, handles, footed, ladle, leafy handle, Southeast Asia, 11 x 12 inches, $975.

Furniture, sideboard, R.J. Horner, oak, carved, mirror back, upper shelf, lion supports, two drawers over two doors over long drawer, paw feet, 79 x 66 inches, $2,520. If you enjoy antiques and collectibles as much as we do, you’ll love Kovels Antique Trader, a vibrant monthly magazine that colorfully covers the field with vigor, insight and curiosity.