Reclaim Spool Storage Command

hi all

i want to get some information about RCLSPLSTG (Reclaim Spool Storage).
when i looking commands on system i found this command and i wonder about 
should i issue this command periodically? When i  get  help for this command i 
learned that spool files stored with database members (may be it will be funny 
for you but i learned now ) . In which library these files resides? And is 
there anything i should  take into consideration before issuing this command 
e.g does it increase CPU usage and users's job waits long or how long does it 
take this command's completion? 
And i saw there are a lot of reclaim commands i wait advice from you that 
should i use these command and how can i use these commands? As i say before 
these questions will be foolish but i need your help to learn about these 
commands....

Thanks to all  


Semiha BALKAYA