FUNCTIONS

i wrote a function do write a file for me on info taken from a db, and wrote a script with a for loop going through every row in the db, and calling the function. so the function is called about 200 times. but i'm getting weird results, the files are corrupted. its grand when i just go one at a time. so i'm assuming variable values must have been left set from the las for loop. so how do i clear ALL variables in the function?? TANX