Hey guys wondering if anyone can help

How does 1 go about setting up 404 redirects for products that have been deleted from my site ,I've seen some that were deleted about 3/4 years ago still appearing , as I am having a major problem with these on google atm and am going round in circles by not fixing these correctly
using the latest version of zencart.
I believe there is a way to do it htaccess or any over way will be fine too

thanks