When a slide is stuck or has been glued in, you can inject a little water and a small amount of heat to free up the slide. Note mixing needles also work good for injecting a little bit of hyde glue in just the right area. Hyde glue will dry inside the needle. To clean the needle, put water in the syringe and then use a heat gun to heat up the needle while you apply pressure. The water will start to squirt out, continue until it's completely clean.
Here is an example of a stuck slide. Using heat and water the slide would not budge. Eventually the perl became unglued from the under slide. I carefully removed the perl and continued applying heat and water to the under slide. In the end I needed to pry the under slide out of the frog. Then I glued the underslide back together using string and then pressing it in a vice until it was dry. Then because the under slide was somewhat warped, I glued the slide back onto the under slide with string and pressing it in a vice whick made it perfectly flat. Then rehaired the bow. . | 
