Stanzabol will jam the needle. What size are you using? If you've done a lot of gear in the past you may feel like the needle is plugged, but you could be in some scar tissue. Sustanon shouldn't smell like alcohol; it shouldn't jam a 23ga needle. Explain what "corking" feels like. I'm not familiar with term and am too lazy to look it up. Sounds like dirty gear, can't say if it's bad or not.