PyRun_String and dictionaries

[Weiss, Mike]

Help!

I've embedded python into my C++ program and I use PyRun_String() to invoke python code. I often do this multiple times per the life of my application. 
For the dictionaries parameters of PyRun_String() I pass "pyMainDict", see code below: 

pyMainMod  = PyImport_AddModule("__main__");
pyMainDict = PyModule_GetDict(pyMainMod);

My problem is that on multiple calls to PyRun_String variables declared in scripts used on earlier calls to PyRun_String() are still hanging around when newer scripts are executed. I assume the problem is that I'm reusing the same dictionaries for globals and locals, the one from __main__.

Is there a run each script in a clean environment, one where stuff from the last run isn't accessible?

I've tries creating new dictionaries and using them but if I use anything other then __main__'s dictionary for "globals" I get strange import errors (my scripts always import other modules). 

I've had some problems with using a new dictionary just for "locals". Mainly when my scripts def" and call local functions (problems with scope).

I've tried to Py_Init before and Py_Finialize after each PyRun_String() call... but that seems to crash.

What's the right way to do this?