How clean is your house? Grime-busting mums take note, as the National Trust’s housekeeping experts reveal their secrets on how to cope with polishing, scrubbing and repairing thousands of the country’s historic treasures.

Even the most domesticated of us could learn a thing or two from the specialist conservators at Osterley Park and House, in Isleworth, and Ham House, in Richmond, who are faced every year with making sure their unusual and exotic objects are spic and span before putting them away for the winter.

Their challenges range from cleaning a 250-year-old tapestry to buffing up a 1920s kitchen range.

Among the traditional treatments used at 18th-century Osterley House is a centuries-old recipe for shining wooden floors that uses blankets soaked in paraffin and vinegar.

Judith Evans, assistant house steward at Osterley Park, said: “We inspect, repair and clean more than 2,000 individual items, carrying on a tradition that in previous centuries would have been practised by the housekeeper and her staff.

“People are fascinated to learn that, although many items are extremely valuable or fragile, it is often the simplest and cheapest cleaning methods that are the most effective.”

Before the opulent houses and their contents are “put to bed” this month, staff will invite visitors to take a peek behind the scenes as the housekeepers set about the task of cleaning and conserving the collections.

The teams will also give house-proud mums top tips on how they can use some of the cleaning methods on their own treasured possessions.

Sarah McGrady, house steward at Ham House, said a five-strong team will get to work on its 1670s and 1740s furniture in 30 open rooms in the building, which was built in 1610.

She said: “Each item has a condition report, a written document showing the condition of the item so we can monitor it during the year and look for warping and cracks, and relate that back to any kind of changes in relative humidity or any over-exposure to light.

“Lacquer is a nightmare because as you clean it the dust sticks on it again. We use pony-hair brushes for most items and a specially made conservation vacuum cleaner to get the dust off the item.

“If you look at dust particles under a microscope they are really spikey – over a long period the spikes embed themselves in the item and cause abrasion.

“But we don’t want to over-clean the collection because too much cleaning will constantly push the dust particles into the items. We need to use a vacuum cleaner to remove the dust once and for all.”

Back at Osterley, some of the objects are so small that the staff use cotton buds and tiny brushes to clean dust gently from the nooks and crannies of items such as the miniature Chinese ivory imperial junks in the long gallery, which have been at the house since 1782.

The servants’ quarters receive just as much attention as “above stairs”. The kitchen holds a collection of copper pots and pans, all of which have to be meticulously cleaned. Gloves are essential for this job in order to protect the copper from the acid on the conservators’ hands.

The team has discovered that a car metal cleaner, Autosol, is most effective because it contains fewer chemicals than other cleaners and does not leave a residue which could attract moisture and cause corrosion. A wax called Renaissance is then applied to prevent tarnishing.

Once the cleaning is done, many of Osterley’s precious contents are protected with their own cotton dust jacket. Everything is covered, from the eight poster bed in the state bedroom to the coal shovel in the entrance hall. More fragile items, such as ceramics and glassware, are protected from dust under acid-free tissue “hats”.

The tapestry room is particularly delicate and normally cannot be entered by visitors due to the fragility of its contents, but a National Trust textile conservation adviser will work in front of an audience in the room later this month, inspecting the tapestries for pests before removing dust using a low-suction vacuum cleaner.

Specialist conservators will also show visitors their work on an 18th-century pier glass – a tall, decorative mirror – in the Etruscan Room.

Visitors to Osterley Park during the conservation in action week, between October 28 and November 1, will be able to pick up a postcard set of care guides, which give advice on how to look after treasured items.

The National Trust will run a Treasure Forever competition, inviting the public to share the stories behind their favourite keepsakes. The competition will highlight everyday objects that mean something special to their owners, rather than antiques or heirlooms of high monetary value.

A panel of judges will select winners from 11 different regions whose object and story will be displayed in their local trust property during spring 2010. Osterley Park and House will display the winning object for the London region.

The public can help choose the Treasure Forever competition winners by casting a vote at treasureforever.org.uk For more information, call 01793 818540 or 01793 818540. The closing date for entries is November 1.