Strikethru Pricing

How can I show a strikethru price (price with a line thru it) on the product detail page and in blocks with any html. I don't see any choices on the tinymce or the product page.

Thank you

By default if you use List_price and it is greater than Price, it will show List_price with a line through it.

Try to switch WYSIWYG editor to the source code mode (< >) and use strike tag. E.g.

old price here

Thanks to both.