Question
I have sprayed my plant and kill the bugs(I think), but the leaves still have the black sooty mold. Many other insects keep comimg. What should I do  to  clean the tree?

Answer
If the leaves aere still sticky after a good rain then you may still have some aphids. Check and see if there is any new honeydew present (should see shinny sticky juices on the leaves). If ther is no new pahid activity then you have controlled the insect.
Once established, sooty mold is not easily removed, but sometimes part of it can be washed off leaves with strong streams of water from the garden hose. The mold gradually disappears after the insects have been controlled.
If the isnects are controlled I would not worry about the sooty mold it only grows on the leaf surface and will slow disappear on its own.