DEAR BOB: You said worthless investment property can be abandoned and can lead to a tax loss deduction: My attorney says he can research it but that seeing a CPA would be cheaper. How can I abandon three desert lots? I'm tired of paying taxes on three sand piles. Evelyn S., Laurel.

DEAR EVELYN: Either an attorney or an accountant familiar with real estate taxation can assist you. To qualify for the investment tax loss, the property must be completely abandoned in the year it became worthless.

IRS regulation 1.165-1(d) and Revenue Ruling 54-581 go into detail. Be especially careful if a mortgage is involved. The mortgage relief can be taxable, unless property handled by an expert.

DEAR BOB: We want to sell business property we own in New Jersey and buy similar property in Florida. But our profit will be large. Is there any way to do this without paying a big profit tax? Henry M., Washington.

DEAR HENRY: A tax-deferred exchange can solve your problem. But you'll need expert help, probably from one or more realty agents and an attorney. The basic idea is to trade your New Jersey equity as down payment on a larger Florida investment property.

But your New Jersey agent will probably have to find a buyer to purchase that property after your tax-deferred "up trade" is completed. It's called a three-way or "cash out" trade. Cross-country trades like this are becoming quite common. It would probably be best to start the trade by finding the Florida property you want to buy and offering the New Jersey property in trade. Then your agent can arrange a "cash out" sale if needed.

DEAR BOB: Your recent reply to a reader explaning how capital gains tax works wasn't complete enough. Many taxpayers think capital gains tax is an extra tax. Some think it is at a 25 percent tax rate. Fewer understand the low rate is to encourage investment. Perhaps you can further clarify how long term capital gains taxation works. Frank P., Kensington.

DEAR FRANK: Sale of a capital asset, such as real estate, common stocks, or business equipment, at a profit can lead to the lowest tax rates available. If the asset is owned 12 months or longer, it qualifies for long term capital gain taxation. Profit on sale of a capital asset owned less than 12 months is taxed as ordinary income.

The maximum tax rate on the first $50,000 of long-term capital gain is 25 percent (rates go up to 35 percent on the balance). But most long-term capital gains are taxed at even lower rates.

The reason is only one-half the long term captial gain is taxed. The other half is the "untaxed half."

Suppose you sell property at a $40,000 long-term capital gain. If you're in a 30 percent income tax bracket to estimate the tax, we divide the profit by two. So $20,000 multiplied by your 30 percent tax rate is a $6,000 long-term capital gain tax.

In addition, the new 15 percent tax preference "minimum tax" applies to the other $20,000 "untaxed half." But there's an exemption of the greater of $10,000 or one-half your income tax paid. If the $10,000 applies, $20,000 minus $10,000 exemption is $10,000 taxable at 15 percent. The total tax ($6,000 plus $1,500) of $7,500 is only 18.75 percent of $40,000, a very favorable tax rate.

DEAR BOB: In a recent answer you said, "Capital improvements are an addition to your home's basis." What constitutes a capital improvement? What about costs of installing air conditioning, major driveway repairs, new appliances, and kitchen and bathroom modernization? Thomas M., Alexandria.

DEAR THOMAS: A capital improvement adds to the useful life of the property, while a repair merely extends or preserves it. For example, a roof patch is a repair, but a new roof is a capital improvement.

All the items you listed are capital improvements, except the appliances unless they are built-in and become fixtures under state law. Painting, by the way, is always a repair. It's often hard to decide if an expense is a repair or capital improvement. Your tax advisor can often help you decide.

DEAR BOB: How can I find investment property that isn't overpriced? The prices on apartments andcommercial buildings here seem too high. Jan L., Fairfax.

DEAR JAN: To find properties that are priced right (1) check the newspaper want ads everyday, call the agents and ask about their unadvertised listings too, (2) meet lots of real estate agents and let them know you'll act fast when they submit a good property, buy it quickly before someone else does.

Remember, asking prices are only the seller's dream prices." Until you make a written purchase offer, you'll never know what the property can be bought for. It's often necessary to make 10 to 20 purchase offers before getting one accepted by the seller so start making those purchase offers.

DEAR BOB: I an a World War II veteran. Am I entitled to a veteran's home loan? Where do I apply? James J., Oxon Hill.

DEAR JAMES: Expiration dates for VA mortgage eligibility have been abolished. If you haven't used your entitlement, you're probably eligible if you earn sufficient income. Get complete details on VA and FHA home mortgages at your local bank, savings association, or other VA-FHA approved lender.

The new report, "How to Sell Your Home With or Without an Agent," is available for 25 cents in coin plus a self-addressed STAMPED envelope sent to Robert J. Bruss, P. O. Box6710, San Francisco, Calif. 94101.