While microwave ovens are great for zapping leftovers, defrosting and other tasks, another small appliance is often overlooked as a time saver.

The slow cooker, introduced in 1971, can do more than occupy space in the recesses of a cabinet. Take it out, dust it off and let it go to work."It's nice to come home to a good smell in the house," said Bert Phillips, home economist for Rival, maker of Crock-Pot.

There is a new generation of slow cookers and accessories. Slow cookers are available with lift-out immersible liners and in squattier shapes that are more conducive to roasting chickens and large pieces of meat. Rival makes a bread-baking pan for use inside the Crock-Pot and a stainless steel meat rack.

"Some people want to own more than one size," Phillips said. "They like the large size for family meals and a small `Crockette' for small servings."

Whatever the brand, most slow cookers feature a stoneware vessel with a low wattage wrap-around heating element. The wrap-around heating feature makes it possible to cook foods for a long time without stirring and keeps vegetables from becoming overdone.

If you aren't getting the most from your slow cooker, here are some tips:

- If converting a conventional recipe to the slow cooker, do not add as much water or liquid. In a slow cooker, liquids do not boil away.

- The flavor of herbs and spices may intensify in the slow cooker. For best results use leaf or whole herbs and spices or add ground ones during the last hour of cooking.

- Follow these time guidelines. If a regular recipe takes 15 to 30 minutes to cook, it will need 1 1/2 to 2 1/2 hours on High or 4 to 8 hours on Low. If the regular cooking time is 35 to 45 minutes, it will require 3 to 4 hours on High or 6 to 10 hours on Low. Something that cooks in 50 minutes to 3 hours will take 4 to 6 hours on High or 8 to 18 hours on Low.

Rival offers two free recipes leaflets, "Dining Light" and "Guide to Adapting Recipes to the Crock-Pot." To get either, write Customer Relations Dept., Rival Manufacturing, P.O. Box 419556, Kansas City, MO 64141.

Baked Beans

1 large can pork and beans (2 lbs. or more), drained

1/2 cup brown sugar, packed

1 teaspoon mustard

3/4 cup ketchup

1 medium onion

1/4 pound barbecued pork shoulder\ Put all ingredients except barbecued pork in slow cooker, stirring to blend. Cook on High for 1 hour. Reduce to low and cook overnight. Stir once or twice.

Add barbecued pork an hour before serving. If the mixture is thin, remove lid for the last hour of cooking.

Crocked Fruit

2 cups peeled apples, sliced

2 cups peaches, sliced, with peel on

2 cups sugar

1/2 cup vinegar

Put all ingredients into slow cooker. Cook on high for 2 hours. Reduce to low and cook for several hours. Stir occasionally. You will have fruit for fried pies or other fillings.

Beef Stroganoff

1 pound beef tips or stew meat

1 package dried onion soup mix or beef onion soup

1 can cream of celery soup

1 can cream of mushroom soup

Combine all ingredients in slow cooker. Cook on low for 6 to 8 hours or until meat is done. If possible, stir occasionally. Serve with noodles.

Spicy Turkey

1 frozen turkey breast, roast or hindquarter, thawed

1 can cranberry sauce

1 small jar orange marmalade

1 cup ketchup

Put all ingredients in the slow cooker and cook on High for 1 1/2 hours. Reduce heat to low for an additional 3 to 4 hours.