Note (1) that 50,000 years is already older than any YEC concept of the age of the earth and (2) there are other deposits without detectable levels of carbon-14, and thus, even IF there are SOME young deposits of coal and oil, the evidence shows there are others which are even older than the dating limits.
Several years ago in a Yahoo groups forum, a creationist had posted/regurgitated the sea-sodium claim pointing out that it showed that the earth could be no older than several millions of years. After educating him on residence times (including aluminum's residence time of 100 years, which H. Morris had mentioned in passing and dismissed with a "huh, wonder what that could mean"), to which he admitted that this claim was wrong and that he shouldn't use it, I posed that same question to him: if your position is that the earth is only about 10,000 years old, then doesn't using a claim that the earth is several millions of years of just disprove your own position? His response was that it didn't matter at all to him if the earth were found to be millions of years old,
just so long as it isn't billions of years old like science says it is.
IOW, the creationist goal isn't to come up with the age of the earth or ages that are consistent with their pre-determined conclusion, but solely to
disprove science.
That exchange also provided me with a big "a-ha!". I also asked him why he kept using such lame and unconvincing arguments. He responded with, "you only find them unconvincing because
you are not already convinced." Aha! So the truth or validity of a creationist claim does not matter, but rather what really matters, the only thing that matters, is that
the claim sound convincing. And to whom especially must the claim sound convincing? To those who are already convinced: the creationists themselves.
Also, despite his having admitted that his sea-sodium claim was wrong, a month or two later I saw him still using it on somebody else. When I cut in to remind him of what he had admitted, he immediately left that discussion ... and I think also didn't post for a while. That taught more something about their ethics and tactics. Or did it just reenforce what I had already learned?