Hi!
xmas and new year are now more or less far away, but wishing you the same as well 
To change your environment in easiest way between the GRID Installation (SID= +ASM) and your "real" DB Instance (SID = "SAPSID", e.g. CP1) use the tool oraenv (bash) or coraenv (c-shell).
Use it this way:
execute as user oracle the command "source /usr/local/bin/oraenv" or for c-shell the same with coraenv. It will ask you for your SID I explained above. Enter "+ASM" and your environment will be set correctly and you'll be able to use asmcmd and other tools.
Cheers,
Alex