Empty cart in show_default.php

-- HikaShop version -- : 4.1
-- Joomla version -- : 3.9

Hello,
I need to clean the cart every time the user enter into the product page, I did it in the past but I can't remembre how I did it ((

I think that I added a comand like this :
$this->removeCart = true;

But it doesn't works... Can you help me?

Thanks Nicolas,
Finally I add this code and it works:

$cart = hikashop_get('class.cart');
$cart->resetCart(false);