A filter, such as the air filter in your car, is used to block unwanted debris, yet allow air to continue through to the engine. A theological filter works in much the same way, it is a mental filter that blocks unwanted information, yet allows the desired information to continue through to the interpretation process. The final interpretation of any given passage will then confirm to the already formulated doctrine of the individual or group. Most all scholars and Bible readers use these "theological filters" when reading and studying the Bible, but are not even aware that they are doing it.
An example of a theological filter at work can be found in the various interpretations if Genesis 1:26 which states, "Let us make man." When one person reads this he will automatically, without any investigation, simply say, "The 'us' is the Trinity." Another person will say, "The 'us' are the angels." Both of these interpretations are created based accepted doctrines, but there is no evidence to support either interpretation.
Even translators of the Bible will employ filters for you. A good example of this is Exodus 33:9 which literally reads from the Hebrew, "and it came to pass as Moses entered the tent, the pillar of cloud descended and stood at the door of the tent and spoke with Moses." According to this verse, the cloud spoke with Moses, but the translators did not like what the verse was implying, so they added the words "the LORD" into this verse so that it now reads, "and it came to pass as Moses entered the tent, the pillar of cloud descended and stood at the door of the tent and the LORD spoke with Moses."
If you want to experience the Bible from a whole new perspective, remove your filters; don't come to the text with any preconceived ideas. Challenge your beliefs by reading the text for what it says. If you find yourself reading a passage of the Bible, and your interpretation is very different from mainstream theology, don't worry; just remember that only a dead fish flows with the "main stream."