Restart. The OS deletes unnecessary cache files. Otherwise, less than 2 GB is nothing to worry about.
Mac Maintenance Quick Assist,
Mac OS X speed FAQ,
Speeding up Macs,
Macintosh OS X Routine Maintenance,
Essential Mac Maintenance: Get set up,
Essential Mac Maintenance: Rev up your routines,
Maintaining OS X,
Five Mac maintenance myths, and
Myths of required versus not required maintenance for Mac OS X for information.
The question wasn't actually answered, so I'll post here as I was looking for information myself. Yes, the cache files are safe to delete. I always make backups before doing things like that, but the "official" word is "yes." Normal auxiliary verbs such as "should" and "ought to" should be applied, of course.
I've still got a Lion Server (hopefully moving to ML Server today if I can get the farking certs to work right) so that's good to know. To give my post context (in case others arrive here) what brought me and to Apple Care and back was the fact I was getting random hard lockups on my system (albeit, custom built). I would see these in the logs every time:
12/19/12 1:06:13.000 PM kernel: Sandbox: sandboxd(89688) deny mach-lookup com.apple.coresymbolicationd
12/30/12 11:41:50.000 AM kernel: Sandbox: sandboxd(79986) deny mach-lookup com.apple.coresymbolicationd
12/30/12 1:07:13.000 PM kernel: Sandbox: sandboxd(6043) deny mach-lookup com.apple.coresymbolicationd
1/3/13 10:49:11.000 AM kernel: Sandbox: sandboxd(174) deny mach-lookup com.apple.coresymbolicationd
Deleted cache, still locked up
1/3/13 1:55:00.000 PM kernel: Sandbox: sandboxd(10713) deny mach-lookup com.apple.coresymbolicationd
I couldn't find any infoz on "com.apple.coresymbolicationd" but found it in the cache. After finding out it was OK to delete the cache, I tried again. Still locked up. I then found a .plist file in /system/library/launchdaemons and moved it. Not a lockup since (fingers crossed).
I know that's not info you asked for, but I like to provide what I can in case other folks happen upon it.
Have a great weekend!