I’m not sure what you mean by trashed. If you mean they were broken and unusable then this shouldn’t happen. There used to be/probably still are a lot of counterfeit usb sticks that report a higher size than they actually are. This could be one reason.
If you mean that you’ve used dd or some tool to create the live usb device and windows is now showing a reduced size (the size of the iso file), then use gparted to create a new partition table. After running that and creating a new partition the full usb stick should be useable again.
It is not necessary to use dd or any special tool. To make a live usb stick all you have to do is format the stick as fat32 (I did this with an MBR partition table on my machine). Then mount the iso file (double click the file in any recent version of windows) and copy everything onto the stick. You must have the folder “.disk” which can be hidden if you are doing this from Linux (change view options in you file manager if this is the case).
Reboot into your (EFI) boot manager. On my acer machine I press F12 just after power on. Select the USB device. You should see the grub menu and bootup is as normal.
To make a persistent live usb stick you need a casper-rw partition/file. Boot the live usb stick. Make it writeable
sudo mount -o remount,rw /cdrom
Create a 2G casper-rw file
sudo fallocate -l 2G /cdrom/casper-rw
sudo mkfs.ext4 /cdrom/casper-rw
Edit the grub.cfg adding the word “persistent” to the kernel command line
sudo nano /cdrom/boot/grub/grub.cfg
e.g. linux /casper/vmlinuz.efi file=/cdrom/preseed/xubuntu.seed boot=casper quiet splash persistent —
Reboot and you should now have working persistence. Test by creating a file on the desktop and reboot again. It should be still there.