Praise be to Allaah.
It seems that with regard to these meals, the company gives them to their employees and workers to keep. The basic principle is that if a person owns something (i.e., it is his to keep), then he may dispose of it as he wishes, Based on this, there is nothing wrong with you taking home what is left of your own meal that the company bought for you, unless the company has specifically stated that nothing should be taken away. In that case it is not permissible for you to take it.
There is nothing wrong with taking the files that have been thrown out and making use of them, because if a person throws something away, the one who takes it becomes its owner. The Standing Committee was asked about cheap or worthless things that are found in the trash but are fit to be used – is it permissible to take them home and use them? They replied as follows: If the situation is as described and those things are things that no one would care to keep, then there is nothing wrong with taking them and making use of them.
Fataawa al-Lajnah al-Daa’imah, 15/455.