1. From your Netscape Inbox window, go to Edit | Message Filters. The Message Filters window will appear. Click on New.
2. Name your filter something descriptive. For instance, if you're blocking all mail that contains the word "mortgage," name the filter "Mortgage Filter".
3. Select the appropriate criteria for your rule. For instance, to filter delete all mail with the word "mortgage" in the subject line, select subject in the first dropdown box, select contains in the second dropdown box, and then type the word "mortgage" in the third box.
4. Select the appropriate action for your rule. In most cases, you will want all mail matched by the filter to be deleted. To do this, select delete it in the next box.
5. It's not necessary to enter a description for your rule, though you can if you want to. When you're done, hit OK to save this filter.
6. Click OK to close the Message Filters window.

You can modify your rules to suit your needs. For instance, you can filter mail based on the subject line of the message, the sender's address, or other criteria by changing what you entered in step 3. You can also change the action performed on messages matched by your filter, by changing the action selected in Step 4.