Need help please!

[MustangMX]

Hey guys im new around here, i have a friend of mine that has a 90g saltwater tank that he has had for 2 years and everything is running fine in it but he has been out of town for months and will not be coming back for a while he has asked me to take it apart for him, What i need to know is how do i store the live rock for him? He sold his coarls back to the lfs so the only thing in the tank is the live rock and some sand, but i need to find out what to do because the live rock has some red algea and bubble algea and some other stuff growing on it so how do i store this rock and clean it because he plans on reusing the rock in a year he told me.

Any help is great ty!