Sandboxie is one of the best security apps around.
After testing several gigs of malware samples through Sandboxie I can say it's been completely secure so far.
Way more convenient running samples sandboxed and just searching through the sandbox for any droppers rather than searching system wide as in a VM.
For each sample you would need to shutdown the VM deleting all changes then fire it up again for the next sample.
With Sandboxie all you need to do after running the sample and checking it out is delete the the contents of the sandbox and chuck the next exploit in there.
Some exploits are both sandbox and VM aware and won't run in those environments but you could employ Buster Sandbox Analyzer which has an option to hide Sandboxie's processes.
www.sandboxie.com :: View topic - Wich is the most secure way to test a virus? (VM+Sandboxie?)