As an alternative to appending visible variables to redirect links to pass them to a destination, or in addition to that, you can embed hidden variables into redirect links. Every time you use that redirect link, those variables will be sent across to the destination, while leaving your redirect links clean of variables, as they are added after someone clicks the link, but before it gets to the destination.

For example, let's say you have an affiliate link on a affiliate network entered in as a destination. It will likely have the affiliate as part of the destination URL, such as "affid=1234" to identify you as the affiliate. That's part of the destination URL in, and will get passed for every redirect link pointed to that destination. 

Then, each redirect link could also have variables embedded into it, to identify to the affiliate network (so you can view it in your stats there) that it was this particular link that sent the traffic.

To do it, go to the management page for the redirect link and click on the "No Variables" button. It's showing you the status, that there are no variables embedded.

And then enter in a reference name, the name of the variable to pass, and the value of the variable:

Click "Save", and then any time anyone clicks on the redirect link, that variable will be appended.

Here's the link I just made:

Notice that even though no variables are appended, when you click on it, it takes you to my testing page with the variables appended, so the end destination is

You can also combine both methods, so you can append extra variables to the redirect link like this:

Which results in both the hidden variable and the appended variable being added to the destination link:

Or, you can override the hidden variables like this:

Where instead of hello being set to "happy" as we specified in the redirect link variable settings, it ends up being equal to "sad".

Once there are variables assigned to a redirect link, when you return to the redirect link's management page, you'll see the status of that button has changed:

Clicking on the "Variables On" button will list off all the assigned variables so you can edit or delete them, which will of course only affect the visits to the link after the change is saved. And, you can add as many variables as want, by clicking the "New Variable" button.