ORIGINAL: mscic-RCU
you could pour some marvel mystery oil in the carb and turn it over a few times. This will help dissolve the castor goo.
Castor oil and petroleum oil do not mix. That is why we do not use mineral oil, even the two stroke variety in our fuel. However methanol, which is what our glow fuel is, readily dissolves and thins castor oil. So MMO will not dissolve congealed castor oil. Glow fuel will.