Hi, sorry, complete noob here. I just started gw2 and I’ve been trying for weeks to get this. What happens is that when I go to Ert and burt’s cave and defeat them as well as all the Ettin, I go to the jar and press F and it just says that it is too strong and is making me dizzy and all it has is an option that says leave so that’s all I can click. Even when I complete this with other players, it’s obvious that they got it and I didn’t. I went through this about 10 times already and nothing is happening. This is the last thing on my map for Queensdale, then it will be 100% complete. Could this be a bug, or is there something else preventing me from getting it? I’d appreciate all the help I can get, thanks. 
Erts Unguent hero Challenge problems
That one gives you an item in your inventory that you can only get once. Look in your bags and double click the item — you can do that anywhere, not just in the cave. That will give you the point.
You should get this item in your inventory when you press F on the jar:
http://wiki.guildwars2.com/wiki/Erts_Unguent
Double click on it, and you’ll get the hero point.
For the longest time, every time I tried to press F all it said was “leave” and there were no options to “take some of the sludge”, but finally after the 5th try today, the option somehow came up and I finally got it in my inventory. I don’t know what was up with that, but thanks for all your answers anyway lol.
what level were you?
i think hero challenges open up at same level as skill challenges used to and thats lvl 13 if i remember right