Some off-the-shelf oven cleaning products are the most toxic and corrosive products you can use in your home. If they are not used properly they can cause damage to your oven. I have come across many ovens that have been damaged due to the chemicals not being applied and cleaned out correctly. Over time, this can sometimes lead to corrosion and rust, because the chemicals carry on eating away when left inside your oven. For example I've seen heating elements so badly corroded that they needed to be replaced, chrome racks completely rusted, and enamel interiors with rust spots,, and white streak stains on and in between the glass door, also beware of using it on the oven door. It sometimes dissolves the glue holding the glass onto the door with disastrous results. In my opinion the lifespan of these ovens have been reduced due to the corrosive damage. I often point out the corrosion and residue stains before I start cleaning and ask what they have used in the past, and it is usually these types of oven cleaning products they have used incorrectly.