Do I have to remove spark plugs that have antifreeze around them for the product to work or do I leave the spark plugs in

If you must, follow the directions on the container. Plugs will need to be left in, if it will work at all.

Here are my thoughts on head/block sealers:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-14.html#post2631647

Keep us informed of how well it works.