Wow! I'll answer this two ways. First, a literal response - wash them. Place them in a washing machine, add the approriate amount of soap, some fabric softener perhaps, and set the machine to do its job.
Second, an critical response. How shallow, insensitive, and disrespectful does someone have to be to post this question? Consider one day child that you too will be old. The karma that you have sown with this singly query has left for your elder years a body odor that will be offensive and barely, if at all, tolerable to others. Good luck with that. Perhaps you can spend the rest of your life making amends and spreading enough good karma to shift the balance in the other direction.
old clothes
Clothes that are not dirty or smell bad.
yousmell
Because they use old perfumes.
The clothes smell bad and need to be washed.
your old clothes.
they just do
Your smell is on the clothes and is familiar to the cat.
Until the clothes are washed.
gasoline odor removal from clothes
wash them.
Burn them