Q: I recently bought space in an old building and took all the covering off a brick wall. It is dirty and dusty and needs a good cleanup. I don't want to go to the expense and mess of having the wall sandblasted, but I want to retain the aged brick look. What kind of cleaner do you suggest using?

A: About the only thing you can us e is a strong detergent such as one containing trisodium phosphate. Scrub it on with a stiff bristle brush, then flush it off with water. Muriatic acid solution can be used if stains remain and you want something a lot stronger, but you will have to be careful about leaving it on too long or it may attack the mortar in the joints. Dilute the acid about 2 to 1 with water, and wear rubber gloves and goggles. Scrub on with a bristle brush, then flush it off with plenty of water.

Q: Recently, our game room was flooded when a pipe broke during one of the very cold spells we had this winter. The room is paneled in rough cedar that has been left natural and not treated. The wood is now stained, especially along the high-water mark from the flood Do you know of any way to remove these stains?

A: Sometimes you can sand such stains out, but you may then have to sand the entire surface of each board if you want a uniform color. The only other cure is to bleach the stains out with a wood beach, but here again you will have to bleach everything since the bleached areas would, otherwise be lighter than the rest of the wood.

Q: Our house has an unfinished attic with loose fill or granular insulation that was put down many years ago. The material looks like wool and is several inches deep, coming to the top level of the joists. There doesn't seem to be enough for today's needs. What can be put on top of this old insulation to make it more effective?

A: If there is no vapor barrier under the insulation, the first thing to do is put one down. Use rolls of polyehtylene plastic for this. Scrape or sweep the loose insulation to one end of the spaces between joists, then spread the plastic film over the attic floor or ceiling below. Next, sweep the insulation back over the plastic and spread it to its original uniform depth.

When the entire attic floor has been covered with a vapor barrier in this manner, and the old insulation replaced on top, you can add to this either by pouring more loose film fiber glass or rock wool on top or, better still, put fiber glass batts with no vapor barrier on top of the old insulation. If you use batts, you can place them across the joists to cut down on heat loss through the wood itself, because the insulation on top of the wood will cut down on heat loss even more than if it was put between the joists.