Rabbosai, it was NOT for cleaning, it was for tevila.  IIRC, the Gaon
doesn't say it HAD to be 300, only that despite 300 being, usually, a
guzma, this is perfectly reasonable (has to do with how many hands
could fit onto the paroches to hold it);  same cheshbon for other
guzmaos in the Gemara.

Gershon
gershon.dubin@juno.com