I typically soak bottles in oxyclean to get the labels off. I also keep a green scrubby and a razor scraper by the slop sink to assist with the stubborn labels and glue.
I don't bottle much any more, but when I did I would frequently run low and then get a bulk delivery of returned bottles. Usually, they were well rinsed and cleaned, but not always. I found you have to remind people every time to save and rinse the bottles.
And, when you run low on bottles it just means you need to drink more!