Cases that Bal Tashchis not apply?
It is Biblically forbidden to damage or destroy any item that can serve of benefit to man, unless one of the following exceptions apply:
Destroying an item for fixing purposes: The above prohibition only applies when one desires to destroy or damage an item for the sake of ruin and destruction. If, however, one’s intentions are to fix or modify, then one may damage it for this purpose if it is not possible to modify it in any other way. [This allowance applies even if one desires to destroy one item in order to fix or build another item, if it is not possible to do so otherwise, and the second item is of greater worth or value than the first item. For example, one may destroy or damage an item that is infringing or threatening another item, if the item under threat is of greater value than the threatening item. Similarly, one may destroy or damage an item that is in the way of another item, if the item under threat is of greater value than the threatening item. Accordingly, we find that the Kohen appointed over the watchman at night was allowed to burn their clothing if they were caught sleeping, as this burning was done for his benefit, so the person prevents himself from falling asleep in the future.]
Destroying an item for bodily benefit: It goes without saying that it is permitted to damage or destroy an item in order to benefit one’s body, such as one who burns a chair or table in order to warm himself up using them, if he has no other wood available. Another example; one may burn a cloth in order to cover the blood [of a slaughtered Chaya or bird] with the cloth’s ash, in order so he be allowed to slaughter and eat the meat, if he has no other dirt/ash available, such as when he is on a ship. The same applies in all cases of the like.
May one destroy items to instill fear upon others: It is forbidden to destroy an item even if one’s intentions is to show anger and fury in order to instill fear upon his household which are not acting properly.
An item which serves no use: It is permitted to destroy an item which serves no use or benefit to people. It is permitted to damage or destroy it for even no purpose at all. This applies even if the item can serve benefit to people, although people do not desire to trouble themselves to reap this benefit from the item, and it is hence rendered useless by the public. [Nonetheless, based on the teachings of the Arizal and Bal Shem Tov, one is to avoid damaging or destroying any item without a justifiable reason, even if the item seems to have no use, such as a mere leaf of a tree.]
It is Biblically forbidden to damage or destroy any item that can serve of benefit to man, whether the item is owned by a Jew, a gentile, or not owned at all. It is permitted to destroy an item in order to save, make room, or create, a more valuable item. It is likewise permitted to destroy an item for the purpose of bodily benefit. It is forbidden to destroy an item simply to release anger and instill fear upon others. It is permitted to destroy an item that is useless, for even no purpose at all.
May one smash a car, fridge, monitor that is found in the dump or junkyard?
If the item can no longer serve any use for parts, then it may be destroyed for even no reason at all. If however the item can be used for parts, and it is common for people to trouble themselves to make use of these parts, then it is forbidden due to Bal Tashchis.
 Admur ibid Halacha 15
 Admur Shemiras Guf Venefesh Bal Tashchis Halacha 14; Bava Kama 91b; Kiddushin 32a; Shabbos 129a; Makos 22a; Rambam Melachim 6/10; Rambam Sefer Hamitzvos L.S. 57
 Admur ibid; Rambam ibid; Chinuch 529; See Tzemach Tzedek 20/4
 Admur ibid regarding a fruit tree, and the same would apply to all cases of the like; See Likkutei Sichos 18/465
 Midos 1/2; See Likkutei Sichos 18/465
 Admur ibid; Shabbos 129a; Chulin 88b
 Admur ibid; Semak 175; Chinuch 529; See Shivim Temarim 53; Likkutei Sichos 18/465
Other opinions: Some Poskim rule it is permitted to destroy an item for the sake of showing anger and instilling fear into one’s household. [Simple implication of Shabbos 105b and Rishonim who rule like this Gemara; Hagahos Maimanis Melachim 6; Tiferes Yisrael Midos 1/2; Ezras Kohanim Midos ibid; Devar Avraham 2/176; Kitzur SHU”A 190]
 Admur ibid Halacha 16 regarding a non-fruit bearing tree and the same applies “To all cases of the like, in destroying other items”
 Likkutei Dibburim 1/112; Likkutei Sichos 38/135
The reason: As every creation has a Divine purposes and contains a G-dly vitality, and it is not within man’s jurisdiction to destroy such creations. [Likkutei Dibburim ibid]