Remove specific characters in bash

I have a bunch of files that look like this:

file1.csv
['Dog']
['Cat']
['Snake']

file2.csv
['Dog']
['Cat']
['Snake']
['Cat']
['Snake']
['House']

I want to remove the [' and '] characters from these files in a loop. How can I achieve this?

The result would look like this:

file1.csv
Dog
Cat
Snake

>Solution :

With tr:

tr -d "[']" < file