If you do not need the data on the tapes - then yes you can reuse them. As you say you used them for testing.
If the images on the tape have NOT expired yet - and you don't want to keep them you can expire all the images on the tape.
You don't mention if you are using the same master server now going into prod as you did for your test - so that all depends.
if you are using a new master - then that master does not know anything is on those tapes and they will appear as scratch.
if you are using the same master and just want to start fresh
(where $1 is the Tape ID)
/usr/openv/netbackup/bin/admincmd/bpmedialist -m $1
/usr/openv/netbackup/bin/admincmd/bpexpdate -m $1 -d 0
/usr/openv/netbackup/bin/admincmd/bpmedialist -m $1
I have a script that does the above commands.
the first command looks up the tape and shows me info
id rl images allocated last updated density kbytes restores
vimages expiration last read <------- STATUS ------->
--------------------------------------------------------------------------------
K00541 8 1 12/13/2009 12:00 12/13/2009 12:00 hcart 91708927 0
1 12/13/2010 12:00 N/A
(will show if it is frozen - and it shows you when it should expire
the second command will ask if you want to expire
the third command is the same as the first - and if the second command worked the last one will say it cannot find it (because all the images on the tape have been expired)
you can script this to do more then one - (I never have had to do more then one at a time)
Once the tapes are not longer assigned you can put them into the scratch pool.