A time will come when you want to change a bunch of objects material in one hit.
A fine example of this would be splitting the material called aggro1 into smaller more portable materials like 'greetowner', 'rewield', 'reguard' etc..
The simplest way to do this is to use the material your objects all share, aggro1 in this case, and add a small block of code to react to tickhour2 which does the material change. Some back after an hour and it will have been done.
Here is a sample material cod that makes sure all frogs get the 'hopper' material:
##tickhour2: runsub changemats;
##changemats:
$mat = $actor's material;
swap $mat take "_junk_"; // this demonstrates the removal of materials;
swap $mat add "_hopper_"; // here we add a new one;
set $actor's material to $mat;
print "[$actor] is now = $rawstring"; // people nearby see a message of the change;
read the info on swap