Mold! How to finance/remediate if I can't appraise?

[Kelly McMillan]

We have an offer on a duplex with some extensive mold. I've dealt with mold, and plan on gutting and renovating regardless, so it is not a big issue. However, I didn't realize our mortgage  broker can't get an appraisal approved if there is visible mold. 

We have several options: 

1. Demand the seller mediates. We won on a best&highest, multiple offer situation (our area is very hot for flippers paying cash), so they are unlikely to do this. 

2. Pay cash, re mediate, and then re-finance. 

3. Extend due diligence, ask the seller to use a remediation company that is paid at closing (apparently this exists)

4.  Other suggestions from the community? 

We are looking at the second option, however, I've not gone through this process before, and hesitant. Mold aside, it's a great investment. Any advice is welcome!