A common way for gunk to get stuck to a clothes iron bottom is accidentally melting fabric by having the setting too high. Designated settings on the iron's label are notorious for directing people to turn the temperature too high for certain types of fabric. Synthetic fabrics such as polyester and nylon then can melt onto the iron bottom. Other ways gunk gets stuck to an iron bottom is by ironing fabric with residue from starch spray, detergent or fabric softener. Ironing material for crafts projects also can cause plastic or other substances to melt onto the appliance. Fortunately, there are many ways to remove gunk from an iron bottom.
Leave the iron on and scrape the melted fabric off with a non-stick coated spatula, half a clothespin or other smooth piece of wood. Be careful not to scratch the iron.
Reheat the iron, if it has been allowed to cool, and iron the residue onto an old towel, which can transfer the melted fibres off the iron. If this doesn't get all the melted fabric off, add salt to the towel and repeat.
Rub nail polish remover onto a cool iron to remove polyester or acetate fabric.
Create a thick paste from 2 tablespoons of baking soda and a little water. Scrub the iron bottom with this paste until the residue becomes loose and can be wiped off.
Scrub the surface with vinegar or vinegar combined with baking soda as a paste.
Wipe the bottom of the iron with household ammonia.
Rub salt onto the iron bottom.
Scrub the iron bottom with toothpaste.
Remove any residue in the steam vents with a cotton swab or pipe cleaner by simply sweeping the vents clean.
Use a sponge, clean rag or nylon mesh pad for cleaning the iron bottom. After cleaning the iron bottom, wipe all the cleaning substances away with water.
Do not use a metal scouring pad of any sort on the iron bottom because this can scratch the appliance. The iron should be cool when cleaning unless otherwise directed.