Use water or dishwashing liquid to help wash off any stains that a simple wipe can't remove. If there are any stains in hard to reach places, use the Q-tips. Use your second piece of microfiber cloth to pat dry your figure. If you use water for cleaning, it may leave water stains if you let it dry by itself.
Put a small amount of soap on the toothbrush, just a small drop, and begin to give the figure, still wet from its soak, a gentle scrubbing. Do not use too much pressure, just enough to clean off the dirt and grime.
0:495:58De-yellowing vintage action figures (toy fix) - YouTubeYouTubeStart of suggested clipEnd of suggested clipBut there's a channel called 20 polloi great challenge guys check out and subscribe and hisMoreBut there's a channel called 20 polloi great challenge guys check out and subscribe and his technique is actually just hydrogen peroxide in a clear container and sunlight.
Dusting. Dusting is the most common method of cleaning you'll use. Your collection and its display should be cleared of dust at least once a month, but once every two weeks is ideal.