I need a cleaning solution for the...

Resist the temptation to use steel wool. It is an effective scourer, but it will leave scratches, especially on older glass. The easiest way is to pour a little kerosene on newspaper and wipe the chimney. (Be sure it is completely dry before lighting the lamp!) Another method is to put a few drops of rubbing alcohol on a wet rag and rub the chimney with the rag.