You may want to call mold remediation companies to see what they offer, some may offer free estimates if you know there is mold. 

Try to find something that cannot be remedied by the seller because most Purchase Agreements are written in such a way that a buyer must give the seller an opportunity to remedy the situation.    

1031 requirements are very specific and a misstep can't be remedied after the fact.

In the contract we used, it does state that "If seller defaults, buyer may pursue all remedies allowed by law and seller agrees to be responsible for all costs incurred by buyer as a result of seller's default."

(credit)If performance fails can the remedies be enforced?

Unless the landlord has given such notice in a termination notice in accordance with § 55-248.31, the landlord shall continue to give a separate written notice to the tenant within five business days of receipt of the rent that the landlord continues to accept the rent with reservation in accordance with this section until such time as the violation alleged in the termination notice has been remedied or the matter has been adjudicated in a court of competent jurisdiction.

Technically to get rid of it you can get certified in lead paint remediation yourself.

You should have used a home remedy of 1/2 snake oil +  2/3 of holly water mixed with 19/143 of vinegar.

If she is trashing the place, there are some pre-foreclosure remedies, but they are not well known. 

But oil tank leaks are a serious thing as remediation depending on the extent could cost 100k or more.