There are two ways to exclude specific companies from your campaigns.
a) Within the app's Campaign Settings, you will see a filter called "Exclude Companies".
b) You can also exclude companies directly via the Search URL two ways.
For example, if you want to exclude Facebook and Google from your campaign you can use the 'Company' filter or Keyword box. The format should be the same for both.
The format begins with the word NOT in capitals and parentheses surrounding the company nam. Add OR (also capitalized) between companies if there is more than one you would like to omit.
The format should look like this: NOT (Google OR Facebook)
*Be sure to only use one tag to string all the companies you want to exclude from the search.*
2. Use the keyword box in the same format.