Large amount of keys generated in Crypto\RSA\MachineKeys\

Hi,

We have a machine of Windows 2003 server + sp2 + IIS6 in production.

We notice a lot of generated keys (about 300 000) in the directory :
"C:\Documents and Settings\All Users\Application
Data\Microsoft\Crypto\RSA\MachineKeys\" which makes backup impossible.

Can we delete all the keys safely?
Or should we keep some of keys to make IIS 6 working? Which ones should
we keep?

Thank you in advance

Don