You can cure the LR
in a can if you want, It is just as easy to cure in the tank. You also will have the cycle of the tank happening as the LR
cures so you will be killing 2 birds with one stone.
If you have LS
then make sure the salt water is mixed out of the tank then added. I would also cover the sand with plastic bags and place a bowl on top of the bags and them fill the tank by pouring into the bowl. This will stop any sand storm you will get.
scrubbing and cleaning the lr
is not needed, take it out of the box and place in the tank is just fine. Rinsing will not hurt anything but scraping the lr
will/may remove any corals or other good things that may have hitched hicked on it.