Many sucking insects, such as scale, will secrete a sticky, sappy liquid that matches your description. Aphids and mealybugs can as well.
"Scales suck your plants juices, stunting the plants growth and they secrete a sticky honeydew which attracts ants and other pests. If it becomes necessary, spray or dip using malathion as directed."
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I'd check for any signs of other insect attack and remove any pests you find with an alcohol q-tip or paper towel. Be very thorough, and keep checking a couple times a week to clean up any stragglers and to break the reproduction cycle. Unless you have a very bad infestation or huge numbers, anything more poisonous shouldn't be necessary.
Good luck!