General :: Script For Deleting Matched Line Of File From Another

I have two text file named 1.txt & 2.txt.

1. txt contains 5 laks of mobile number.
2. txt has 60 laks of mob no.

Situation is that I want to find and delete numbers in 2.txt which already in 1.txt. Any perl or bash script or any other way to get the work done.

I tried the following:
#! /bin/bash
IFS=$'
' for NAME in $(cat one.txt)
do sed -ie "|^$NAME$|d" two.txt done
echo "***DONE***"

It works well with smaller file but it take very very long time even processing 10 thousand numbers.