Welcome to the forum , Gleek .
A stiff nylon/bristle brush & some liquid Dawn + warm/hot water + elbow grease might do well enough for the job , unless you're planning on refinishing your items .
These were not designed for 'dainty' stuff & often would get funky &/or warped/bent from 'improper use' .
I would not sweat much about cleaning off the soot from unpainted areas , unless lots of rust is present .
You can use a variety of simple products to give a protective coating to your iron item , once it's clean enough for you ... ranging from the simple lamp black , paste wax , mineral oil (& so forth) to specialty coatings .
If the soot on your item(s) is thick/tough to clean , it may be due to it being a 'protective' layer over rust , so proceed scrubbing with a bit of inquisitive caution .
Using a mild solvent is another way to remove soot/carbon on UNPAINTED iron - ones like turpentine , lamp oil etc .
Pressure-washing (atop an old pc. of carpet , etc.) @ the local DIY carwash is another method (again , for the unpainted areas) that some folks would use .
I'd stick to cleaning them with non-metal implements only , if it was my chore to do .
Thanks for posting , Gleek .