Glass cleaning

Summary: A quick introduction to glass cleaning

Most contaminants on glass fall into one of three categories

• Waterspots
• Road dirt
• oily residue (fingerprints, vape residue, cigarette smoke…)

For the first either you need a Waterspot remover or you polish/abrade them away (especially if they have etched) unlike on paint, where a first step chemical removal is key – on glass you can just polish after claying. Sometimes a good regular glass cleaner is enough. 

General Road dirt/General interior dirt – Here is where stuff like a diluted Rinseless wash or your regular glass cleaner works awesome, almost all glass cleaners tackle this mostly well. This part is where technique matters. 

Lastly is the oily residue, no matter if it’s a dirty hand that touched the glass with a lot of finger grease or stuff like vape residue – this is a case where you might need more solvent based specialty cleaners, such as some specific glass cleaners or a panel prep/ IPA mix.

Keep in mind that any solvent based product will stress gaskets and seals and any trim it comes into contact with, so only use when needed.

Often overlooked but just as often the reason for streaky windows is bad residue control. After a good cleaning, detailers are many times not chasing dirt or dirty residue but rather cleaner residue from overusing a cleaner. My recommendation is to use a non barrier sponge, spray your cleaner on that, do cross hatches and then remove with a clean dry towel.

For the windshield a reacher tool is a very helpful addition to your detailing arsenal. Underused and underrated on glass is steam. As much as steam sucks in most parts of detailing it’s a lifesaver on glass as ultimately it’s just distilled water and will evaporate streak free, and due to its heat has surprising power against dirt and even oily grime. Steam can be the ultimate tool if you are chasing bad cleaner residue too, for example on a car that a customer tried but failed way too many times where you have basically a layer of cleaner residue that you need to cut through first.

One thing to keep in mind is that most cars have factory installed coatings that can not be replaced on the side and potential back windows (rarely on the front) and these should only under the worst circumstances be cleaned with abrasive materials as you will never be able to replace them with something of a similar performance.

Also some windshields have an invisible layer of plastic for a heated windshield or HUD, and these can be very scratch prone and sensitive, making you need to use extreme caution.