Lichen looks like this in its natural state. It is usually found growing on rocks in dense forests. Lichen is soft after a rain (wet weather is the best time to pick it), but it becomes hard and brittle during dry weather.
After the lichen is removed from the processing solution (top), it must be drained and squeezed to remove most of the liquid. Then it can be spread out on newspaper to dry (bottom). It's a messy job.
Processing Your Own Lichen
by Dave Frary
Few modelers elect to pick and process their own lichen, but for those hardy few, here's how to do it. The first step is to find a source of natural lichen, which grows in wet, wooded areas all over North America, from Central Florida to the Arctic Circle.
Gather several large plastic bags of lichen from the forest and take it home. The next step, and the most time-consuming part of the process, is picking through the lichen to remove pine needles, sticks, bits of leaves, rabbit pellets, and the unusable coarse portions of the lichen itself. You'll throw away two-thirds of what you brought home (it's great garden mulch), but if you've found a good stand in the forest, what remains for processing will be much finer than anything you'll find in a hobby shop.
Unprocessed lichen will not keep. It will either dry out, get brittle, and handling will reduce it to powder or, if left damp, will get moldy. So plan to process the lichen as soon as possible after it's removed from the woods.
Always process the lichen outdoors to keep the heat and mess out of the house. You'll need a picnic table and a camp stove, and on the stove you'll need the biggest tub or pot you have, one that holds at least five gallons. On one lichen-picking trip I brought the processing equipment with me and spent the best part of a weeks vacation camping and preserving lichen.
BASIC LICHEN PRESERVATION SOLUTION
3 gallons water
1 gallon commercial-grade glycerin*
*Buy the cheapest commercial-grade glycerin you can find; It will still be expensive. Check your Yellow Pages for a local chemical supplier.
Dissolve 1.5 packets of green powdered fabric dye such as Rit or Tintex in the basic preserving solution. To give your lichen realistic variety, buy all the green dye colors that look like foliage, plus several shades of yellow. Start with the lightest colors, and every time you dye a batch of lichen replenish the glycerin and add a darker dye.
Heat the glycerin, water, and dye solution almost to its boiling point. The ideal temperature is about 230 degrees Fahrenheit - close to a simmer. Stuff as much lichen into the pot as the solution will hold, continue heating to return the solution to a simmer, and simmer for 5 minutes. Remove the pot from the stove and set it aside to cool. When the solution has cooled enough that you can stick your hand into the liquid, remove the lichen. Wearing heavy rubber gloves, grab a big handful and squeeze out all the liquid you can.
Reheat the glycerin solution to process the second batch, replenishing it with the following:
REPLENISHING SOLUTION FOR A 4-GALLON BATCH
1.5 pints fresh glycerin
1 packet dye
Use a packet of the next darker shade of dye. I usually pick so much lichen that processing it takes an entire day. The last batch should be the darkest, almost blue-green.
As you remove each batch from the pickling solution, spread the lichen on newspaper to dry, turning it frequently. I like to do this outdoors, in the sun, but even so, the processed lichen often takes two or three days to dry. At night, stuff the lichen into plastic bags and bring it indoors. When the processed lichen no linger leaves visible moisture or green color on your fingers when you squeeze a piece, store it permanently in the same plastic bags.