Detailed Explanation 

1809-2009 implicates the following laws

I. An unpaid trustee or gratuitous bailee assumes liability for damages due to  negligence [Choshen Mishpat 291: 1].

II. A gratuitous bailee commissioned for a definite period of time is absolved from  damages resulting from negligence, following the circumscribed time. [Machane Efraim   Shomrim 19] (The rules for a bailee for hire differ. See further issues.)

 
III. Following the circumscribed time, the former bailee may not damage the deposit  and remains accountable for damaging or similarly removing the deposit to an unsecured locale [Choshen Mishpat 319, Igros Moshe]

IV. A trustee appointed for an indefinite period of time must confer with the depositor or the Beit Din (Halachic Court of Law) before relinquishing his or her safeguarding duties and previous level of liability [Choshen Mishpat 293:3].

V. The mitzvah of Hashavat Aveidah; returning a lost article, requires the finder to safeguard the find and notify its owner of its whereabouts [Choshen Mishpat 259: 1].

VI. While safeguarding the find, the finder is deemed a gratuitous bailee appointed for an indefinite period of time, and is liable for damages or losses due to negligence as long as the safeguarding responsibility has not terminated [Choshen Mishpat 267 Sm"a 17, Schach 17].

VII. Upon notifying the owner of its whereabouts and providing ample retrieval time, the finder terminates his/her duty and like any former gratuitous bailee is henceforth absolved from damages due to security negligence. Nevertheless, the finder may not damage the article nor remove the deposit to an unsecured locale [Choshen Mishpat 267: 16].

VIII. Generally, one may legally bar others from intentionally depositing articles in his/her home and should theoretically be permitted to clear the premises of unsanctioned deposits intentionally placed therein [Choshen Mishpat 319].

IX. Relocating the unsanctioned deposits into a secure area is permissible. With authorization and assessment from a competent Beit Din (Halachic Court of Law), the homeowner may even deduct the storage/moving costs from the belongings. [In the event that storage costs exceed reasonable value, A should sell it or may purchase it for him/herself and inscribe the value in his/her ledger to be paid to the owner upon claiming the belongings] [Choshen Mishpat 319]

X. However, unless the homeowner urgently needs the occupied space and lacks alternative recourse [Choshen Mishpat 383:2]., the depositor's thoughtless impositions does not justify damaging the unsanctioned deposits or placing them into a precarious position without warning the depositor and providing ample time to retrieve the deposit. Indiscriminately damaging the deposit , simply to teach the depositor a lesson is forbidden. [Rosh Bava Kama 101b, Rama 319:1 Sm"a, Taz].

Example. A parked her truck in B's driveway. B needs the spot today. B may not slash A's tires or indiscriminately cause A financial loss simply to teach A a lesson. However, B may have the truck towed or take the necessary steps to clear space for his vehicle, expenses billed to A.

In the event that the homeowner unlawfully relocates the unwarranted deposit to an unsecure locale, and damage or loss ensues, competent Halachic advice should be sought whether compensation is in order.

Application:

1809

Landau issued general permission for individuals to store their belongings in his home until the danger abated. Landau became a gratuitous bailee for the valises deposited in his home until the danger abated. Although, Frankel overstayed his welcome, Landau may not damage his valise nor put it in a precarious position without forewarning Frankel. Although inconvenienced, and challenged by the anonymity of the valise's owner, Landau may only pitch it out in the yard, if he needed the space immediately and had no other recourse. Otherwise, he must safeguard the valise, or receive authorization from the Beit Din to place it in a secure rented storage room and charge Frankel for the cost of doing so.

As damage ensued from the valise's unlawful relocation to the unsecure locale, Landau should consult a competent Halachic authority whether any compensation is in order .

2009

Molly fulfills her Hashavat Aveidah responsibilities by informing the previous tenant of the received mail. [ In a area with a reliable postal service, leaving it for the postmaster and writing return to sender would suffice.]

As long as Molly does not inform the previous tenant of the accruing mail, she assumes Hashavat Aveidah responsibilities and must safeguard the mail. Once Molly informs the previous tenant of the incoming mail, she need not take precautions to safeguard the mail.

 Nevertheless, she may not remove the mail to an unsecure locale   nor discard pertinent mail without giving the previous tenant warning (and ample retrieval time) of her plans to do so. Discarding the mail would only be permitted if Molly needs the place immediately and has no other recourse. Mail, which unquestionably clear that the previous tenant is uninterested in it, may be discarded