clean install and where is the .dmg i downloaded

[shamguy4]

i installed lion...and now i can't find the .dmg

now i have to download it all over again for my other mac.
is there a way to take the installer off from the recovery mode?

also can I do a full clean install and remove everything with recovery mode because I was thinking of getting rid of a lot of garbage and stuff i probably don't even know about like hidden caches and what not.

 

[portishead]

There is a thread already:

https://forums.macrumors.com/threads/1191839/

 

[shamguy4]

that doesn't make sense i shouldn't have to redownload it.
there is a recovery mode which i should be able to boot into and clean everything out?

im a bit new to this stuff, but I'm a fast learner... doesn't a clean install erase everything and install a new clean version of the OS on my mac? and isn't there a separate partition so i don't have to download it again?