Thanks folks.
Don't like it much when the pigment starts to solidify, or worse.. turn to sticky sludge.
I don't mix custom colors often enough, but then again, I still need it around for when I do.
Must keep it viable for some time.
Anyone care to share what the actual medium is for pigment?
I use Wilflex PC stuff, but I'd imagine it's all similar. (?)
Cheers.