The script has several system traders, they are displayed in the 2nd table, which is below the table with your traders. You cannot delete system traders. Currently there are the following system traders:

• exout – it can only have outs.
• noref – hits without referrer. This system trader can have outs if you redirect such traffic, and clicks from such surfers.
• nocookie – can have clicks and outs. Clicks - when a surfer clicks without cookies, outs - when traffic without cookies is redirected somewhere according to settings.
• notrade – hits from domains that you don't trade with. There can also be clicks here - these are clicks from surfers who came from domains you don't trade with, as well as outs if in settings you specify that such traffic should be redirected somewhere.
• cheat_url – can only have outs if you redirect clicks that the script considers cheating.
• proxy_url – only outs if clicks are redirected through a proxy.
• in_redirect , out_redirect - only outs if you redirect incoming hits or some clicks according to Traffic Rules settings
• SE – traffic from search engines, here there can be ins and clicks, i.e. incoming traffic from search engines and clicks made by these surfers.
• Overclick – all clicks from any trader beyond the norm specified in Max Count Clicks (Settings). In fact, all clicks from overly active surfers are credited here.
• Blocked_ref - clicks with empty referrer or referrer with a domain other than your domain.

NOTE 101 here and in all other settings means use the default skimming.

Imagine a situation: you have a site where a surfer came from Google (SE traffic) and at the same time from a phone (mobile traffic). SE has skimming 70 and mobile 80 - which skimming should be applied? Now you can change the order of skimming application in Settings - CJSettings - System traders. You can drag (drag&drop) the trader's position in the list. The higher in the list the higher the priority. For example, if mobile is above SE, then the skimming will be 80.