You can use RedMowse or any other ghost mouse program. Just record dropping the inventory once, and every time you need a drop just tell the program to run once.
program new;
{$i SRL\SRL.simba}
begin
SetUpSRL;
Repeat
If InvFull Then
DropAll;
Until(False);
end.
I can write you up one for Simba in a few minutes easily.
What are you dropping, or do you want it to work with any items?
Can it drop all slots or just specific ones?
Wouldn't a program like stated above always use the same coordinates though? That's not good.
Use the script I pasted above, also are you familiar with MouseKeys? It's a windows (and other OSs) too feature that is legit and allowed that lets you drop things fast.
Read about it here:
http://runescape.wikia.com/wiki/Mouse_keys
I've made a script that simulates mouse keys so it drops really fast in a 'legit' way but you don't have to do any work, example of it running here:
http://www.youtube.com/watch?v=i1PQlmBYOQo
very nice its similar to the 1 i used to use
Make sure all of those 'mouse recorders' have randomness built in or you will get banned for following the same pattern and clicking same exact pixels each time!

