Hi Mel, I'll move your thread to the    "Cultivation Problems  " where it may be better placed.  

Here is one suggestion from Michael Campbell, one of the many really accomplished growers in the forum: 
Are  you are looking for a solution to a liverwort problem? I use Baking powder (Sodium hydrogen carbonate) Mix one teaspoonful with a little very fine sand, sprinkle it over the pots and water it in. Doesn't appear to affect the seedlings, well not here anyway. 
You could also try a search of the forum to see if the information you seek is already here . The search button to use is the one fourth from the left in the row of options  show a near the top of every forum page.
From such a search, for instance, we find there is  one thread with liverwort in the title :
http://www.srgc.net/forum/index.php?topic=4636.0   and two pages of results from mentions of liverwort in other threads, All sorts of remedies are mentioned - Epsom Salts, vinegar, potassium permanganate ( doesn't work for us!)  and so on .....
We don't use vermiculite so I don't know about  liverwort in that specifically. 
Also, as well as the official Help button which assists with general info on the use of this SMF forum  - there are more notes specific to the SRGC forum here : 
http://www.srgc.net/forum/index.php?topic=2.0