The recently added Caustic Sink Launchers are great. They automatically take care of caustic damage and take far less space and attention than using decontamination drones.
But they work a little bit differently than anything else in the game in that they can be partially used up but only the total number is permanently saved in your state.
So for optimal use:
- Just before restocking, launch any even partially used Caustic Sink. That allows you to buy a completely fresh one. And they are only 10 credits each!
- If you have a partially used Caustic Sink and log, it will automatically be discarded. Presumably that is so because FDev didn't want (1) to save the state of the sink or (2) allow you to refresh your sink by relogging. That's fine, but remember to fill up your sinks before relaunching the first time after a log or you may be one sink short.
Source: https://www.reddit.com/r/EliteDangerous/comments/11rzvoh/tiny_tip_cycle_your_caustic_sinks/