It really depends what dialect you're speaking.
In standard Oxford English, for example, the "t" is pronounced, but often not released (as BobK describes) in the words you cite. In many British dialects, such as Cockney, it is replaced with a glottal stop: the airflow is cut off at the back of the throat.
In many British dialects, the combination "tl" (as in "butler" or "bottle") is often pronounced as a click sound for which we have no separate letter, similar to (but not exactly like) the kind of lateral click which is a feature of some African languages, like Xhosa. It sounds a bit like a mixture of "k" and "l", and indeed small children learning to speak are apt to say "bockle" for "bottle".
In old-fashioned BBC English, the "t" was enunciated and released very, very carefully. BBC English was used on the radio in the days when reception was often very poor, and so a deliberately over-careful pronunciation helped listeners decipher what was being said against a background of pops, whistles and interference.