Dear James: One room has old plastic tiles and I want to remove and replace them with more modern tile. What is the most effective method to remove the old hard adhesive? — Billy T.

Dear Billy: Preparing the wall for the new tiles is always the most difficult part of the project especially when the old tiles have been up for many years. Don't give up and just put the new tile over some old adhesive. It may neither adhere well nor lay evenly. It will definitely look like a do-it-yourself job.

Since they are cheap old plastic tiles, don't worry about breaking them as you remove them. The edges may be sharp, so wear heavy gloves. As you pry them up, they may first bend and then shatter. Also wear safety glasses so none of the small flying pieces get into your eyes.

Once you have all the tiles removed, use a stiff hand scrapper to remove any of the large loose pieces of adhesive. Unfortunately, as you have found, most of it will be too hard to even dent with the scrapper.

There are several different types of adhesive removers you may try. These soften the adhesive so it "easily" (so the packaging states) can be scrapped off the walls and floor. Realistically, you can still expect to do some serious, arm-tiring scrapping, but you will be able to get it off.

Citric acid-based adhesive removers (liquid or paste) are the easiest and safest to use. The liquid type is easy to spread on the floor and the paste is most effect on vertical surfaces. It would be wise to have some ventilation when using any chemicals, but the vapors and odor are not strong. Cleanup is usually done with water.

If you gave the citric acid remover time to do its job and the adhesive is still too hard to scrape off, try a soy-based remover. Since you do not know what type of adhesive was used, you may find the soy-based remover is more effective. As with citric acid removers, soy-based ones clean up with water.

You may have to try some stronger solvent-based adhesive removers if the other types did not work well. There are more hazards when using these, so pay very careful attention to the safety precautions. Most of these will not clean up with water, so make sure to purchase some of the cleanup chemicals at the same time.

Providing proper ventilation is important when using these solvent-based removers. If you are working in a small room, such as a bathroom or kitchen, the vapor concentration can build up quickly.

Don't just spread the remover on and walk away because the adhesive may soften and then get hard again when the solvents evaporate. Follow the timing described in the product instructions.

When you finally get the adhesive removed from the walls and floors, select a new adhesive which is consistent with the type of new tile and the floor and wall substrates. When you are finished with the project, save the old can of adhesive even if it is empty. The cleanup and removal instructions on the old can label will come in handy many years from now when you or a new owner decides to replace the tiles.

Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com. To find out more about James Dulley and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.