Another Sync Bookmarks Question

Just got a new macbook air and setting it up it defaulted to iCloud enabled before i could turn iCloud off..

I usually don't use iCloud.

Anyway, I noticed on the new macbook air iCloud brought in some bookmarks but there were a mix of older bookmarks and current bookmarks.

Where is iCloud getting this mix from? Why older bookmarks?

Since I now have two macs, iMac and the air, how can I share the correct and current version of bookmarks (from the iMac) with the Air?

How can I get rid of these bookmarks on the Air, then bring in the "good" set from the iMac?

I don't really understand iCloud and wondering how and why older bookmarks are even stored in iCloud?

And how can I get rid of these older bookmarks from always coming in on new devices?

Just the good stuff.... please.