There are multiple things you can do that we know about.
- You can store contraband on your outposts
- Sell it off with the Trade Authority. I think you can even buy back the same item you sold and have the item come back 'clean' or laundered
- Get a shielded cargo hold. I am not 100% sure how this works when scanned but the theory I think is that you need to mask the contraband with legit items to make it work effectively. There is also a shielded capacity for contraband and go beyond that it becomes less effective.
- Get Scan Jammer which should help masking the contraband. There are different types, some more effective than others like so:
- Scan Jammer – Single-Frequency: 10% chance of avoiding scan
- Scan Jammer – Dual-Frequency: 30% chance of avoiding scan
- Scan Jammer – Multi-Frequency: 50% chance of avoiding scan
I think some of this is still being worked out as more hours are sunk into the game but this is the gist of it right now.