You may be surprised to know that Cleanse will remove all stacked viscosity damage, or at least I was when I found out. That’s quite a boon for the common Viscosity and something to consider the next time you get that enchantment. It can be particularly useful if you play with the Faith is my armor challenge.
It does help somewhat, but with a lot of challenges, its very niche because I don’t upgrade armor nor do I rarely use upgraded armor with a lot of challenges (Faith is My Armor especially). Because of this, I usually have very little Viscosity dmg stacked, and I don’t always need to use up a cleanse during those times (they’re extremely useful when doing a high number of challenges). I will say i have used it more frequently against spiders because their poison dmg is very annoying.
I still haven’t incorporated FIMA into my challenges, still at 5, but I think an accessible combo like this can help build my experience with FIMA on. But yeah, I imagine with 9 challenges or around thereabouts, this would simply be an option in a wide slew of tools that would need to be employed to survive.