I've just discovered a very interesting myth, and it's persisted for years on the wiki despite being totally false.
The myth is that "for every unit of material size an item has, 1/10th of a bar of that item's metal type will be recovered".
This has never been true.
I first discovered this while studying a disassembly of version 0.23.130.23a - I found the code for determining melt yields, examined it, and found that all of the melting yields were constant, based solely on item type and stack size. Curious to see if it was still the case, I found the same code in 0.34.11 and found that they did respect material size, but they returned 3/10 instead of 1/10 per size unit.
Then I started looking at older versions to see when it changed. What I found shocked me - aside from adding new item types, the code for determining item melt yields has not changed a single bit between version 0.23.130.23a and version 0.34.05, which is when it changed to the current behavior.
I could not track the exact origin of this information, but it was first added to the 40d page when a user imported it from the archive wiki where it pertained to 0.23.130.23a (where it was obviously false) and nobody ever verified it, and the same information has been blindly carried forward to every new version released since. This is absolutely shocking to me, and it means that a vast amount of information on the wiki can possibly no longer be trusted.