(Probably a much longer response than you want, but ...)
There have been a HUGE number of reports on several threads over the years about yellow or green "gunk" or "slime" forming on valves from various Hetman valve oils. Just go on Werden's forum and search for these. Some people absolutely love the Hetman valve oils, and some people just can't live with them. Over time, the consensus response to this has been to conclude that there are combinations of instrument metallurgy, body chemistry, and lubrication products that either work well for an individual or are a disastrous mess.
It's just seemed that over the years, the "disastrous mess" reports involving Hetman seem higher than in other cases -- but this is hardly a scientific study or conclusion. I used to use Alisyn valve oil on my rotary tuba, and I still do use it for internal rotary valve lube on the trombone. But after a number of experiments I found that the Yamaha synthetic valve oils just worked best for me in other circumstances, particularly piston valves -- and I use different viscosities (typically light or medium) depending on the instrument and state of the valves. I also prefer an odorless,tasteless synthetic lubricant to "dino oil" for anything I'm blowing into. In my experience, the synthetics just work better (in instruments, in cars and motorcycles, etc.). The only place I can't use one is in my outboard motor -- because (according to the manual) it provides too much lubrication and the motor won't run hot enough!!
There's just a LOT of anecdotal evidence (which seems consistent with the science) that some of these things don't mix well with some players, and others do. In a similar vein, I absolutely CAN'T use Blue Juice valve oil. Not that it doesn't work well, but I just can't tolerate the smell. Even sitting next to someone using it is uncomfortable for me. But it has a big following among euphonium players. On the other hand, I use a lubricant/protectant called "Ballistol" (
https://ballistol.com/about-us/) on my firearms (particularly my black powder rifle), and the smell doesn't bother me at all. But it drives my wife crazy and I have to carefully clean up every residue of it and get rid of all rags, paper towels, etc. and get them out of the house. And this idiosyncratic reaction to Ballistol has been well known for over a century.
There's a lot of personal variability in how you or your instrument may react to a given lubricant. I just stay away from the Hetman products -- except for Hydroslide, which seems to work well for me.