Question
I checked for insects as indicated in a previous response, there aren't any. Half of the tree's leaves have a clear sap which also ends up on the floor. No yellowing or dropping of the leaves, just sticky sap. A few are dying but not dropping. Thank you.

Answer
Hi Paula,

I have checked the log, and I don't find a question from you that I have answered.  So, I am assuming that you found a previous question that mirrors your problem. Here goes!

This sounds very much like scale insect infestation, especially the sticky sap on the leaves.  These insects can be extremely difficult to find as they do not move once mature.  They affix themselves to branches, leaves, etc. to suck the sap from the plants.  The cannot use all of the sugar that is contained in the sap, and their excretia presents itself as a clear, very sticky "honeydew".  

Adult scale insects appear as oval to circular, flattened discs approximately 1/16 to 1/4 inch (1.5 to 6.5 mm) diameter.  They range in color from tan to dark brown/black, and can be found also on undersides of leaves and stems.  The juveniles (crawlers) are motile and appear as white to tan, fluffy flecks.  They find a feeding spot, attach, and develop the hard, waxy covering that appears in the adults.

Scale insects are difficult to control. There are several well-known remedies that can be tried in an attempt to eliminate scales from a houseplant. However, there is no easy, simple cure for a scale infestation. One possibility is to pick off individual scales or gently scrub (or rub) the scales loose from the leaves and stems. This is a laborious task that works only on small, large-leafed plants. Dabbing each scale with an alcohol-soaked cotton swab is another possibility on lightly infested plants.

Sprays can be used for scale control. Success will depend upon thoroughness and persistence. Insecticide sprays (aerosols or hand pump sprayers) made just for houseplants are available at garden centers. You can use a mild dish washing detergent in place of the commercial insecticide soaps. Use a dilute solution of 1 Tbs of detergent per quart of water. Soap sprays can be applied with a sprayer or used with a soft cloth while washing infested leaves and stems. Insecticides must be applied thoroughly, repeatedly and persistently (weekly for a month or more) to get good control.

Once the weather is reliably warm, it is good to place your plant outdoors where natural predators can control the scale population.  Move the plant first into a shaded position to allow it to adapt to the brighter light conditions.  Gradually (over the course of several weeks), move the plant into a high light area.  Ficus benjamina (weeping fig) and Ficus elastica both prefer full sun, provided there is adequate water.  Some Ficus species are very sensitive to changes in environment and temporarily drop their leaves.  This is especially true of Ficus benjamina.

Hope this helps.