I just don’t feel like it would be hard to put a picture on the thing of a guy like getting close to it then dying. The basic idea that it’s hazardous wouldn’t be too hard to communicate.

That would certainly stand a higher chance of conveying the right message than overengineered solutions like monumental spikes or attempts to impart taboos against certain colours of cats or tablets that combine an English dictionary and a nuclear physics lecture

But still, I think the natural response to a picture of a person grabbing an ancient container and dying is the stuff inside must have been valuable for them to have attached all these threats to it. At least that's the conclusion drawn by Egyptologists translating inscriptions like "the great lords of the west will reproach him [who breaks the seal] very very very very very very very very much". (I'm not joking about the number of instances of the word translated as "very"...)

I think at the end of the day, the best we can hopefully for is that only one or two people grab the valuables inside, then everyone else realizes the curse is no joke and tosses the crate back into the ground.

So, the solution is to bury a small piece of unshielded highly radioactive material at the entrance, just enough to lethally irradiate the first party that breaks in? ~

If I were really trying to do a good job of it, I’d try to come up with the way to mix the waste into a hard brick too large and heavy for one person to carry, but cart-able for two or three. Perhaps i’d even use a mold to make it look deliberately manufactured to discourage breaking it apart. This way, hopefully, the waste wouldn’t be scattered in small pieces before the community realized what was happening. Hopefully, then, whatever party came into possession of the brick would #1 very visibly possess it and #2 very quickly show signs of illness. Alongside all the other safety measures, I’d hope this would very quickly tell the community that obtained it how dangerous it was while minimizing the scope of harm it ended up causing. I don’t personally see how anything better can be achieved here if we’re assuming this culture has lost all traces of nuclear physics and can’t understand any languages we have, and disregards any pictographic warnings we put on it.

Yeah. The only lesson that would be learned from a bunch of tablets depicting agonizing death to those who approach would be "I'll make sure to send the low-paid workers in first before I go in".

Yeah, that’s true unfortunately, but it would also give people a very quick answer if they asked why x person was growing sick: because they brought the curse upon themselves etc. My hope would be that very few people would have to “demonstrate” the curse’s veracity before the culture tossed it back where they found it. It would especially help if the pictures depicted how to deal with the waste once it was realized, eg show some people putting all the material back into the crate then burying it deep in the ground, or in its original location.

“An awesome great weapon is buried there. We must dig it out and use it on our enemies”.

I feel like if at the point we lost knowledge or technology and the ability to understand what is buried there, does the effort matter that much? Or to put it another way, if we are back in the stone age, some nuclear waste that is buried is the not biggest problem.