I don't like using a blade since it can scratch anything -- even glass. Although, if you're really delicate you'd probably be OK.
I strongly recommend naptha (a.k.a. VM&P) which is available at Home D or any paint store. It's highly flammable and has tons of fumes so use in a well ventilated area with no risk of spark. Naptha dissolves adhesives and does not attack paint. That's what it's designed for. 3m adhesive remover is another choice and available at most auto supply stores.
I love naptha and I've used it every time I want to remove anything like an adhesive or anything gummy -- even old grime smushed into the pores of bare wood. I like the smell so much it's embarrassing... Since it liquifies the adhesive, you want to keep a clean bit of rag exposed at all times or you'll just rub glue all over the place which will then dry in a matter of seconds. Naptha will evaporate in much less than a minute.
Also, careful with rag disposal. Naptha soaked rags can actually spontaneously combust under certain circumstances. I recommend unfolding the rags and exposing them to lots of air -- hanging them like you would towels on a laundry rack. They'll dry in just a few minutes and then they're safe for the garbage cans. The official recommendations is to put them in a metal can filled with water and take them to the hazmat disposal site. But, that's asking a lot.
A side story about naptha...
A friend's wife was working for a tanker shipping company that had two tankers which hauled naptha all over the world. One day, one of the ships just wasn't there anymore. It basically vaporized when the naptha ignited. So, note to self, smoke after you're done with the job and don't do it in the garage with the old water heater with a pilot light. It strikes me as at least as combustible as gasoline.