This thread sparked a question in my head. Imagine that you are in a situation where you need to dispose of you wallet seed backup, but it is etched on a steel plate - how would you do it? The easiest answer is likely acid, but not everyone has access to it, and depending on the steel plate, it might be even highly resistant to corrosion. Another option is to damage it mechanically - in many of these steel plate products you are supposed to etch the words, so it should be possible to erase them or render unrecognizable. But it's likely hard to do thoroughly and traces of the words could remain.
Any more ideas?
The method is nice, it is your personal decision whether you dispose of the seed backup on a steel plate, but many may find it complicated to save the seed phrase of the wallet. I personally am not able to engrave steel metal, seems too complicated to me. If I do have the help of an outsider to do this, such as someone who is an expert in metal engraving, my wallet is completely vulnerable when the seed phrase will go to him if he is involved in crypto currency. Anyway, I saved my wallet seed phrase in a few steps so that it can be easily accessed in any medium. If you forget to save the wallet seed phrase you can easily lose it, and if you are aware of it you can save it anyway with personal effort.
It's hard if you are not into those mechanical stuffs and then you lack in the right tools but we can always call the help of someone else who are expert on it and I think we will know if those people are into crypto or not and if they are trusted to not steal our coins.
We can also do some measures to prevent them from doing that because it may be hard for us to know their true identity completely. Another safer and easier option (though may not really be cheap) is to simply buy a same type of wallet or seed purse. I already saw a couple of those before. When creating a wallet we are always required to write them down because memorizing them may not be easy and even if we do for a while, there's still a high chance that we can forgot them later on.