Cleaning a cast iron pan is no problem. Cleaning a waffle iron can be a pain in the ass. This $12 chainmail scrubber gets into the nooks and crannies..
Fucking waffles. I have no idea why, likely it is just happenstance, but every now and then a waffle sticks to the iron. Admittedly, using a cast iron waffle iron is more art than science. You don't want to over oil it. You better not under oil it, and oh-for-gods-sake do not forget to oil it at all. Whatever I do, occasionally a waffle gets stuck.
It is no pleasure getting waffle remains out of a heart-shaped waffle iron, let me tell you. The first thing I try is simply making a new waffle on top of the crusty remains of stuck waffle! Sometimes new waffle pulls dead waffle right the heck out! I suggest undercooking new waffle just a bit. If this does not work I move on to the chainmail scrubber.
I've reviewed the chainmail scrubber before, people told me I'm crazy. Ignore people, this thing is great! The links on this chainmail scrubber work perfectly to fit into the waffle-channels and grind out stuck, dried waffle. I'm not going to bullshit you and pretend this is an easy job, but I usually find a medium effort pass with the chainmail, and a quick rinse with warm water and a sponge, will get everything cleaned out. If it doesn't, making a new waffle in whatever is left over always finishes the job.
Chainmail won't hurt the seasoning on your cast iron. The seasoning on my waffle irons is always flax, and I use spray canola on them while cooking. Every year or so I'll run lightly flax oiled irons through the oven at 450F or so for an hour, just to clean them up.
Chainmail also works great on a skillet.