[Richard]

I have a homemade Tilt-style hydrometer in a watertight cylinder with a screw-on top. The top cylinder has some indentations which catch krausen and can hold some dried gunk after the krausen falls, causing the calibration to be off by a bit. It isn't a big deal, but I have been trying to find a material that I could use to fill up the indentations and make a smooth surface on the top without affecting the beer. I see that MoreBeer sells beeswax for sealing oak barrels (https://www.morebeer.com/products/oak-barrel-sealing-wax.html ). It seems to me that this would be a good material. It shouldn't react with the beer in any way and shouldn't give off any aromas or flavors. Is that correct?

[chinaski]

I think it would be fine and you could heat it up to render it sanitized when you apply it.  Not sure that it would solve your problem though as its pretty tacky and I think trub and krausen would stick to it as well.  Try it and see.