Jaya Radhe! Can someone explain me about broken idols of deities? There was a broken Buddha in the apartment building I live. I read they had to be thrown into the river or lake but what karma has a person of they place the deity in front of another's house? More directly, not properly disposed?
An idol which is broken should not be worshipped. It should be given to a flowing river or to any water body.
Quoting from Chapter 14 of Mahanirvana Tantram:
[Lord Sadashiva says] The wise man should not worship the image of a Deva which is broken or is holed, or which has lost a limb, or has been touched by a leper, or has fallen on unholy ground (100). The image of a Deva with missing limbs, or which is broken or has holes in it, should be consigned to water. If the image has been made impure by touch, it should be consecrated, and then worshipped (101). The Mahapithas and Anadi-lingas are free from all deficiencies, and these should always be worshipped for the attainment of happiness by each worshipper as he pleases (102).
So, such idols should ideally be immersed in rivers, lakes etc.