A friend of mine had a problem with a 50ml vile of Test Enan that had a small leak. I transfered it to another sterile vile through a 0.2um filter and a 18g pin. I vented the vile with a 25g pin. After the transfer I removed the 18g pin and baked the vile with the 25g pin still in. The problem is that when the vile is pressurized there is an air leak coming out the of the 18g hole. I don't think anything is going in, but is this normal? It would be almost impossible to filter 50ml of oil based enan through a smaller pin, so what can I do to prevent these leaks?