.DS_Store

This seems like a bit of a scam:
On your external drives you can prevent the creation of .DS_Store

defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true
defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true

If you really want to continuously delete DS_Store from both your internal and external hard drives you can set up a cronjob:

15 1 * * * root find / -name '.DS_Store' -type f -delete

When I had a Mac, literally the first thing I did was set up a Hazel rule to delete every single .DS_Store in every folder.