Removing currency symbol, except on Woocommerce cart and checkout pages

I want to remove the currency symbol from my webshop, except on the shopping-cart page and the checkout.

So I do NOT want a currency symbol on:

• category pages
• product pages
• home page
• landing pages
• blogs

But I DO want the currency symbol on:

• shopping cart
• checkout pages
• confirmation e-mail

I have been given this code:

function avia_remove_wc_currency_symbol( $currency_symbol, $currency ) {
    if ( !is_cart() || !is_checkout()){
        $currency_symbol = '';
        return $currency_symbol;
    }
}
add_filter('woocommerce_currency_symbol', 'avia_remove_wc_currency_symbol', 10, 2);

Which removes the currency symbol from all pages. It doesn't make it reappear on the shopping cart or checkout pages.

Try this:

<?php
    function avia_remove_wc_currency_symbol( $currency_symbol, $currency ) 
    {
        $currency_symbol = '';
        if ( is_cart() || is_checkout()) 
            $currency_symbol = '$';
        return $currency_symbol;
    } 
    add_filter('woocommerce_currency_symbol', 'avia_remove_wc_currency_symbol', 10, 2);

?>