What Is A Query String?:
A query string is a part of the URL that contains data that doesn't conveniently fit into the structure of the URL.
What Is A Unwanted Parameter In Google Analytics?:
The query string parameters are unwanted because they have no real significance in the URL, if they did we wouldn't want to remove them.
Removing them would not affect the data at all.
How To Remove Query String Parameters:
To force GA to skip certain query string parameters when processing we enter the unwanted parameters in GA as follows :-
1. Go to your Google Analytics account.
2. In the top menu click on Admin (usually the fourth & last option).
3. You get three columns of options usually.
4. In the right hand column titled www.yourdomain.com or something, click on View Settings.
5. Scroll down to 'Exclude URL Query Parameters' field.
You will find the query strings in your URL and they normally follow \?