Will aspirin disolve an existing blood clot?

The trick is to take the ASA prior to the clot formation. Once the clot forms it has to be stabilized , so that the bodies own inherent clotting system can start dissolving the actual clot that has formed in the affected tissue vascular system .

No. Aspirin may prevent clot formation and even for that there are more effective medications. Clot lysis requires enzymes like tPA and streptokinase.