NodeJS Memory Leak when using VM to execute untrusted code

I am using the NodeJS VM Module to run untrusted code safely. I have noticed a huge memory leak that takes about 10M of memory on each execution and does not release it. Eventually, my node process ends up using 500M+ of memory. After some digging, I traced the problem to the constant creation of VMs. To test my theory, I commented out the code that creates the VMs. Sure enough, the memory usage dropped dramatically. I then uncommented the code again and placed global.gc() calls strategically around the problem areas and ran node with the--expose-gc flag. This reduced my memory usage dramatically and retained the functionality. Is there a better way of cleaning up VMs after I am done using it? My next approach is the cache the vm containing the given unsafe code and reusing it if it I see the unsafe code again (Background:I am letting users write their own parsing function for blocks of text, thus, the unsafe code be executed frequently or executed once and never seen again). Some reference code. ``` async.each(items,function(i,cb){ // Initialize context... var context = vm.createContext(init); // Execute untrusted code var captured = vm.runInContext(parse, context); // This dramatically improves the usage, but isn't // part of the standard API // global.gc(); // Return Result via a callback cb(null,captured); }); ```