If it weren’t the first time and it fell on a maintenance cleaning (let’s say monthly to keep it simple) I would be comfortable taking this account for $35-$45 for exterior only & somewhere around $65-$75 for inside and out. And this pricing is 100% based on our area and the quality of service we deliver so just remember this is what I would price but everyone has their own way of doing things. Honestly man the suggested price of $125-$150 is fair and square for a construction cleaning when you factor in paying for insurance, taxes, your equipment, your time and most importantly the LIABILITY that is associated with using razors, not saying you would scratch the glass but using a razor comes with a waiver and etc. Hope this helps!