To clean the plate from the iron, I had to use the whole thing but at least it cleaned very well

It does what it promises and does it very well. Just be careful in its use. It is better to be done outdoors and with a mask.

I had a steam iron that was in terrible condition underneath. I had tried various techniques over time (e.g. using aluminum foil) and they did indeed extend its lifespan quite a bit. Unfortunately, they didn't work anymore, so I tried this specific stick and it worked perfectly.
Basically, you rub it on the hot plate (unplugged) and it dissolves everything. However, be careful of the fumes. You must do it in a well-ventilated area and wear a mask, otherwise you will inhale all the chemicals.