Don't clean antiques too well

When dust, body oil, grime and oxidation occur on our drapes and upholstery, we call it dirt and go to great efforts to clean it off.

When it settles on our bronze sculpture or folk-art collection, it is called patina and we wouldn't touch it if we were paid to.

Cleaning some family heirlooms can reduce the value tens of thousands of dollars. Consider the poor lady on an "Antiques Roadshow" episode who scrubbed her Tiffany lamp base clean. I don't blame her--the polished bronze base and sparkling shade looked absolutely stunning. But where an untouched lamp may have been worth $50,000 or $60,000, hers was worth something like $10,000.

I must admit that I don't get patina. In many instances it looks like dirt to me. In fact, I don't even pronounce it correctly. Most of us say "pa-teen-a" to rhyme with "Katrina," yet the "Antiques Roadshow" Web site says it is pronounced "pat-in-a" to rhyme with "cat-in-ya."

However we say it, "Roadshow's" Keno twins, Leslie and Leigh, go bonkers over it. They explain that patina tells the story of where the piece has been, how it was used and where it came from. In many instances, true patina can authenticate a piece and separate the genuine from fakes.

So the question arises whether to clean or not to clean an antique piece. The rule of thumb: If in doubt, don't. It is always safer to preserve patina until the piece is appraised and you know for sure whether you are inadvertently removing the history that makes the piece interesting.

According to the "Antiques Roadshow" Web site and other antiques experts, here are some tips on what to clean.

Ceramics: yes. With warm soapy water and soft, lint-free cloth.

Glass: yes. With warm soapy water and soft, lint-free cloth.

Wood furniture: yes. Clean, but only with beeswax and soft, lint-free cloth. Don't strip.

Painted furniture: no. There is a history there in the chipped paint and stenciled decor.

Silver: yes. But only with a mild silver cleaner and soft cloth.

Bronze and copper: no. Patina is appreciated and valued on these pieces.

Jewelry: yes. With distilled water, dish soap and soft cloth. Do not soak.

Toys, dolls, stuffed animals: no. Best to store these items in acid-free paper away from light and moisture.

Textiles: no. Leave cleaning and repairs to the experts.

Clock mechanisms: yes. Take your clock to a repairman to keep the mechanism clean and ticking on time.

Oil paintings: yes. Have these cleaned by an expert.

Needlework: no. Store safely in acid-free paper away from light and moisture.

Posters, framed prints: no. Only a conservator can remove water marks and mold from printed items. Make sure they are mounted on acid-free paper.

Books: no. Dust only. Keep away from heat and moisture.

Guns: no. Store safely to protect from heat and moisture. You may paste wax the barrel.

Coins: no. Patina is appreciated and valued on these.

The "Antiques Roadshow" Web site contains a vast assortment of information. Go to pbs.org/wgbh/pages/roadshow/index.html