A trick I use is adding a sanitized hydrometer right into the fermentation vessel. If you do primary in a glass carboy like me, you can check on the gravity in real time without exposure to oxygen/contaminants.
One issue I've had is yeast/trub clinging to the hydrometer tip after krausen, it...
I took mine completely apart just now, cleaned all the surfaces with windex and it looks brand new. I too stood my refractometer upright (eye piece on table) and got wort inside the lens. It was rather easy to take completely apart. Check out the photos.
I found that a can of compressed air was...