The votive candles in St. Mary's chapel are lit frequently, and each day, the old candles need to be removed, excess was removed, and new votives replaced. Anywhere from 20-60 candles are lit per day, so this important task requires many volunteers. Most volunteers clean 25-30 candles holders per week.
Volunteers are assigned on a weekly basis (one volunteer has Mondays, another has Tuesdays, etc...), so this ministry can be suited to fit your schedule. Volunteers take the used candles home to clean out the wax (melting them in the oven, then wiping out the residual wax with a paper towel works well), and return them to church the following week, putting in fresh votive candles. Detailed instructions are available.
If a new votive candle is placed into a red candle holder that has not first been cleaned, the remnants of the old candle will cause the wick to tip against the glass, causing the glass to shatter. This brings to mind a passage from the Gospel of Matthew...
"People do not put new wine into old wineskins. Otherwise the skins burst, the wine spills out, and the skins are ruined. Rather, they pour new wine into fresh wineskins, and both are preserved."