Ok so I looked around and tried to search but I didn't find anything and frankly not to sure exactly what to search for. I am looking for an app that will go through and clean the phone up and optimize the memory from anything unwanted or unneeded from old apps that I have deleted and tinkered with. I know that uninstalling the app removes most of it but not all of it. I read on Android Central that there is still some left over cache that drags down the memory a bit and some apps leave some folders with useless files. A couple people said there is apps to remove the cache to free up some memory and those folders and files but they never said what the apps were. If anyone knows of any or if it has already been posted and I'm not searching for the right thing please help me out.

Thanks in advance. 

I'm also not sure what to search for, but this thread is prolly the most relevant to my concern...

I have all my web downloads go to a folder called "Downloads" and it is slowly filling up with files with names like Download-1.apk, Download-2.apk, etc. 

I've dug around inside those files and they seem to be compressed system and software files for various apps I got from the market.  If anybody can explain them more, I'd appreciate it.

Are these files only involved with the initial installing process, and no longer needed?  Can I delete them with no crazy consequences?  Or are they necessary and referenced as apps are running(if so, can I move them?)? 

I want to keep this folder organized, if possible, but don't want to delete anything that's critical for operation of software.

I been meaning to ask about this for months lol.