Q: I have a dull gray plastic tile on my kitchen wall. I am now removing this tile, but I am finding that the glue is very hard to remove. Is there an easier way than hours of scraping?

A: Since you haven't told me what kind of tile was used (plastic or ceramic), I must assume that you are talking about plastic tile that was applied with adhesive. Most of these adhesives will dissolve with either lacquer thinner, acetone or paint remover. However, these solvents are highly inflammable, so if you do decide to try them, be sure there are no open flames nearby and that there is plenty of ventilation. I think you may be better off renting a belt sander and using this with a coarse to medium grit paper - it will probably be faster, less costly, as well as being safer.

Q: You have rightly advised people through your column not to apply linseed oil on cedar shakes because it tends to develop mildew and darkens greatly with age. However, we applied linseed oil four years ago. What can we do now to clear up these problems?

A: The first thing I would to is scrub the shingles to get rid of the mildew and some of the surface dirt. Use a solution made by mixing one quart of fresh Clorox with three quarts of water, to which you add a couple of handfuls of a strong powdered detergent. Scrub on with a stiff brush, then rinse off with plenty of water. If there are still dark spots remaining, the only choice you have is to apply a shingle in a darker colour to camouflage them.If there is no serious problem with dark sections, and if you want to retain the natural look and color of the cedar, then I would suggest applying two coats of either a clear wood sealer, or a colorless creosote shingle stain. These products are sold in most well-stocked paint stores, as well as in many lumber yards.

Q: I have an old pine dining table which has been waxed or oiled with lemon oil for many years. I now want to refinish this table with a low luster varnish so that it will be easier to keep clean. How can I remove the oil without damaging the antique patina before applying the varnish?

A: The patina you refer to is basically the finish - and in your case this is the wax and oil used. Removing this will remove most of the patina, although the color may remain at least in part. However you must remove all the oil, wax or polish before you can apply any varnish - otherwise the varnish will not dry properly. you can remove this oil and wax by scrubbing with a pad of fine steel wool, which is repeatedly dipped into paint thinners. Do a small section at a time, then wipe up promptly with plenty of rags before the solvent starts to dry again. Chances are you will have to go over each section twice if there is many years of accumulation on the surface. Remember that the solvent or thinner is flammable, so dispose of all rags promptly out of doors (in a metal pail). As a final precaution, I would advise applying a thin coat of shellac as a first coat (one part shellac to two parts alcohol) to seal the surface, in case any oil or wax remains in the pores.

Q: I bought an old summer house and want to redo the floors which now have old tile and linoleum on them. What is the best method for removing these old floor coverings so that I can then sand the floors?

A: To remove the linoleum, work one corner loose, then start pulling it up while you scrape with a stiff putty knife or a long-handled tool, such as the kind used to chop ice off sidewalks and stoops. Linoleum cement is water soluble, so after you have raised a section start mopping hot water underneath to help soften the cement and ease the lifting job. It will come up in pieces, but this can't be helped. When all of it is off, scrub the entire floor with hot water and use a scraper to remove as much of the heavy caked-on cement as you can before sanding.

To remove the tiles, you will probably find a small torch or heat lamp helpful. Heat each tile, then pry one corner up and force a wide putty knife underneath. After the first few, the job will go faster if you use a hammer to tap the scraper under the tiles, but continue to use the torch on stubborn ones. The idea is to heat each tile enough to soften it, not to scorch it or set it on fire. After the tiles are all up, use coarse paper for the first sanding to get off the adhesive that remains.

Q: Is there any way I can apply a hard, scratchproof and stainproof finish to my maple dining table so that I can use it without having to cover the entire table each time we dine in the room?

A: There are very hard varnishes, known as bar top varnishes, which are sold in many paint stores. One of these, or a urethane varnish, can be applied to give a fairly tough finish that will be alcohol-resistant and also resistant to most food stains (if they are wiped off promptly). Two or three coats will be required. However, I would still advise using place mats to protect against scratching, and avoid placing hot pots or dishes directly on the surface.

Questions about home repair should be addressed to Bernard Gladstone, Do-It-Yourself Clinic, Home Improvement Department, The New York Times, 229 West 43d Street, New York, N. Y. 10036. Only those questions of general interest can be answered in this column.