One of the most profitable ways to cash out Taste of Lacre is in the Nadir, where you can trade 7 points for a Vial of Tears. That’s… not reliable, but you have several weeks of Nadir visits to look ahead to.
The Sample of Lacreous Affection seems to be valued at 312 echoes, but currently does not have a way to actually cash out. Personally I’m going to collect a few. There’s an outside chance it will have a use come Jan 18.