I did one in my dishwasher last week and was peeved that when it finished the little bottle was full still.
I HAD pulled the sticker off. The remaining seal is wax.
Unfortunately what I hadnt noticed was the sticker I removed left a flim over the wax plug so while the wax melted the film didnt allow the liquid to come out.
I took the lid off the bottle, scraped the film off then melted a candle to plug up the hole again.
Ran the dishwasher again and it was happy as larry and clean as a whistle.