Process of elimination using Dots instead of Numbers.
When you are putting possible numbers that can be in a square. Use Dots instead.
No need to use a Rubber.
Use a bolder dot to represent Hidden Pairs etc.
. . . Top row represents 1,2 & 3.
. . . 2nd row represents 4,5 & 6.
. . . 3rd row represents 7,8 & 9.
. These 3 dots represents 1, 5 & 9.
I hope it can help some people.