What are "Sipos Kesef Mezamros"?
Rashi: They are musical instruments.
Here it forbids using money of Bedek ha'Bayis for Kelim. In Divrei ha'Yamim II, 24:14 it says that they did so!
Radak (citing Kesuvos 106b): The money may not be used for Kelim, but if they collected and there was extra money, the excess may be used for Kelim. This is why it says there "when they finished