free cached memory

[gmorais <gmorais@deea.isel.ipl.pt>]

when I use free in command line I get:

                      total       used       free     shared    
buffers     cached
Mem:        449300     219144     230156          0       5560     149084
-/+ buffers/cache:      64500     384800
Swap:            0          0          0

my question is:

there is any problem || related to the fact that my cached memory is so 
much occupied?

and if there is, how can I free it?

Thank you all!!

gmorais