Although there are quite a few special candies trapped in Bubblegum you shouldn’t focus on activating those as soon as you can. Instead, you should focus on making special candies yourself and use those to clear the Bubblegum and activate the trapped special candies. With candies of five colors on the playing field you shouldn’t have too many problems making special candies.
Since candies move from the top to the bottom of the playing field, match candies as low on the playing field as possible as often as you can. Doing this will shift the largest amount of candies and hopefully start a chain reaction that will create new opportunities to make special candies.
While your attention is at the bottom it’s easy to forget about making special candies at the top of the playing field, so pause after every move and glance at the entire playing field to see whether you can make special candies. It’s worth making special candies even if it means the Bubblegum spreads a little. You can clear a lot more Bubblegum with a special candy than you can by matching candies on top of Bubblegum.