Re: Flash drive mayhem
Hi populus2 and welcome!
With respect to the 64GB card, there is a slight chance that you may have caused it irreparable harm by disconnecting it in the middle of a write operation. If a block is being written and the power fails, this would toast the whole block. If the block holds partition content, you would scramble its partition. And if static was involved, the card could be toast. Although the card won't mount, is it even recognized? Connect it to a USB port with your reader and open Disk Utility. Can it see the card at all? If so, you may be able to salvage the card at least by repartitioning it.
With respect to the 32GB flash drive, you mention that it is old. What have you done with this drive in the past? Flash drives have a limited number of write cycles, but it is unlikely that you would have exhausted those unless you wrote to the drive incessantly. Did you defrag the drive constantly or install a full OS on it? Most check/repair utilities will also perform many write operations (that's how it checks) and were designed for HDDs and not flash drives. There's so much variation in USB flash drives that it's hard to advise you on this one. USB flash is dependent on the quality of its components and construction, efficiency of its controller, how much free space is left for load balancing, and can be quickly degraded through heat, shock or water, especially water.
Frankly, if you cannot get the 64GB card working again, I would advise you to purchase another USB stick rather than try wrestling with the old one. They are absurdly cheap these days (Best Buy on sale for $9.99) and you will waste far more than ten bucks worth of your time trying to chase down what is wrong. Of course, if you are treating your time as an investment in the learning process, then that's an entirely different matter, but most people just want to solve the matter and get on with life.
Newb: How far must I jump to clear the ledge halfway down?
Guru: It's bad to jump off cliffs. Let's look at better options.
Newb: Stop harping about "best practices" and just let me jump.