Found a solution, but only for the woof woocommerce attribute filter plugin. I’ll just leave it here for anyone who might need it.
there are these rules in the front.css file in plugins/woocommerce-products-filter/css which have to do with the icon.
.woof_products_top_panel li span {
padding-right: 16px;
background: url(../img/delete.png);
background-size: 12px 12px;
background-repeat: no-repeat;
background-position:
Where there is “../img/delete.png” I can use any url I want, making sure not to have that ../ and that I have https:// otherwise the path will always be relative to the woocommerce-products-filter folder. I just have to make a folder for the plugin in the child theme (themes/nameofmychildtheme/woocommerce-products-filter/css/), copy the front.css file there, change the code so that the url points to the image I want to use.
There. You can permanently change your delete.png image in woof woocommerce filters.
GGWP.