abp in firefox doesn't really remove them. I've seen and reported multiple scummy popup-like looking ads like tfn and saw it again for weeks...

There may be gaps every now and then in block lists of ad blocking solutions, but besides that, you are using the wrong ad blocker. abp is not to be trusted to reliably block all ads it could. It has a different mission than uBlock Origin.

Use ublock origin rather than ABP. ABP was dead the moment they sold out to "responsible" ads.

ABP as in adblock plus?

Don't use that. Use Ublock Origin.