Cleaning up an iMac for giving away?

[RgrF]

If thats the usage and it's for a 13+, I'd leave it at 8.6. That was maybe the most stable OS I ever used. A 333 will struggle with any version of X, why make it do what it was never intended to do?

I have an old 500 and doubt I'd want to upgrade it to any version of X.

Maxing out the RAM to 512 is always a good idea for any OS.

If it has more than a 6 gig drive, it'll have to be partitioned with the start up OS8.6 in the 6 portion.