Clean old instaled packages

Hi,

In /Library/Frameworks/R.framework/Versions , I see the installed 
packages for all the R versions that I had:
2.13    2.14    2.15    3.0    3.1    Current
Is-it safe to remove all the previous instals and keep only 3.1 and the 
alias to Current ? I just put them in trash ?
Thanks

Marc