Can I get rid of my Premium Raid Passes?

April 2019 Update:
You can now delete your Raid Passes by simply clicking the 'delete' button.

Legacy info:
There's only one in-game way of deleting those Premium Raid Passes, which is as user SHRLY has suggested - just join an ongoing raid and leave them repeatedly until all is used up.

Alternatively, you can also email Niantic support and ask to remove your Premium Raid Passes (as well as other non-deletable items like Incubators), by going to the Niantic support page and selecting "Purchase Issues".

You can now delete them after applying the latest update

Yes, I had same problem, they can not be deleted. I join raid left raid, join raid left raid,... that is only way how to rid them off.