Thumb drive slowing down. TRIM command fix it?

I got a 16GB Lexar USB2 thumb drive. At first it seemed to write at an OK speed, but now it writes very slowly. After I filled it up to transfer to another PC it still had several GB of space used even though it showed up as empty in Windows Explorer. I quick formatted it to empty it completely. Now it slows by the minute. Is there a TRAM command to restore it to new condition.

OTOH its FAT32 file system might be the problem. I did a full format on it instead of a quickie. Maybe that will work.

Format won't clear cells. Try diskpart from command prompt -> diskpart , list disk , select disk ( and here number of your thumbdrive ) , clean all
This will clean whole drive. Later format it to exFAT32 or something like that.
Diskpart is also great when you have weird problems with SSD ( boot issues, F4 errors while installing OS etc ) as it's cleaning firmware area and boot sectors what standard format is not touching.

have some free time, clean all will take a LONG time, even with 16gb.