how to restore folding glass fireplace screen?

glass is loose in the brass framing; have high temp black caulk; unsure if cauk will run when temp rises

should be able to use... lighter fluid, to clean the glass and if it's brass... some brass cleaner
High temp. caulk might not be the answer. "High Temp" caulking is not usually intended for fire use. More likely for heaters or engines... something like that. A local fireplace store in your area should be able to supply you with a metal-fabric seal that fits between the glass and the metal. (Sorry, I can't remember what it's called.) Also, whatever you do, don't damage the glass. Most fireplace screens/doors have a special glass called Neo-ceram or Poly-ceram, which is extremely expensive. And I can't express enough how extreme the expense is, but here in Canada you could expect $100 or more for a square foot. Anyway, sounds like nice project. Good luck!