[PD-dev] How to free memory of t_symbol

I have a data structure with a symbol and an array of symbols that store array names defined as:

``` t_symbol **x_weights_arrays; t_symbol *x_biases_array; ```

When I'm done with them, I want to free the memory, but calling free(x_biases_array) doesn't seem to work, and once called, as soon as I try to do something else in Pd (like unlock the patch and choose an object), Pd crashes.

I have narrowed down the error to freeing these symbols, and I'm sure the crash is not caused by something else. I scanned m_pd.h to see if there is a function to free t_symbol memory, but didn't seem to find anything. This might be something obvious for C-savvy people, but I'm not one, so any advice is welcome.