Hi Thunder,
You need to appreciate that the moon's surface is very rough, about the colour of bitumen and is transmitting reflected light only. The light intensity of the Sun is about 30,000 times that of the Full Moon. The moon appears so bright, because everything else is so dark. You will not damage your eyes looking at the moon. The moon when observed in its brighter, waxing gibbous phases, in a scope with an aperture over 4", appears very bright. The larger the aperture of the scope the brighter it appears. When you look away from the scope after observing the moon for a while you get the "ring of fire", this is a transition thing only. Three things happen when you look away, your eye's pupil is rapidly dilating, the chemicals which assist with dark adaptation are flowing rapidly (photopigment regeneration) and your eye is changing the visual receptors that it uses for vision from Cones to Rods. It's exactly the opposite effect to opening the curtain in a dark room with bright sunlight outside or turning a bright light on when you have been sleeping. Its unpleasant for a few seconds but no damage results. Countless thousands of people, including myself, have observed the moon unfiltered for decades without issue.
When observing the moon alone I always observe it unfiltered, it takes a little getting used to but you will get there. Throw in a few F's and B's as the light hits and this helps you get through those 1st few seconds
When I have inexperienced observers with me, like my 9yr old son, or my wife, or at school viewing sessions etc, I use a variable polarising filter on the moon for the comfort of the other observers.
There are a couple of things you can do to make it easier for you to get used to observing the moon unfiltered (and bright planets for that matter).
1. Turn some outside lights on. You only need to have dark skies to observe dim targets, not bright targets. Don't turn lights on that are likely to cause troublesome reflections in the telescope, but enough to increase the exterior brightness levels so that you "don't" get dark adapted.
2. Increase the magnification. As you increase the magnification, the exit pupil reduces, which dims the target.
Ultimately visual astronomy is all about extracting as much detail as possible from the chosen target, to do this you need to maximise the number of photons that reach the eye. Don't waste them, they are precious
CS-John B