mouse:
take da mouseball out and wipe it
clean da rollers wif ur fingers or use a cotton stick thingy mabob
monitor:
use vacumn cleaner 2 get rid of da dust in da vent
use cleaning fluids and a lint free cloth 2 clean da screen
use lint free cloth 2 clean da casing
floppy:
dunno, buy a new 1? since dey r so cheap
cd rom:
dunno, cause da "laser" is very fragile. not sure if it is cleanable
keyboard:
turn da keyboard upside down and tap it so all da dust and dirty stuff comes out
wipe da keys wif a lint free cloth