What treatments have you had for seborrheic keratosis?

I have hundreds of SebKs on my back, and now it's starting to crawl up my neck and face. I think there are just too many to do cryo or other one-by-one treatments. Has anyone had chemical/medical treatments? I prefer topical treatment rather than pills, for now at least. Googling suggests vitamin D formulations like tacalcitol, maxacalcitol. What have you tried? What was the effect? I'd really like to hear your experience.