Write a function to balance parentheses in a given string by removing the fewest characters possible. Ensure that each opening parenthesis has a corresponding closing parenthesis and each pair is properly nested.

To balance parentheses in a string by removing the minimum number of characters, you can iterate through the string using a stack. When an opening parenthesis is encountered, push its corresponding closing parenthesis onto the stack. When a closing parenthesis is found, check if the stack is empty or if the top element doesn't match. If either is true, it's an invalid pair. If it matches, pop from the stack. After iterating, if the stack is empty, the string is balanced. This approach ensures proper nesting and matching of all parenthesis types (e.g., '()', '{}', '[]'). The time and space complexity are both O(n), where n is the length of the string.