Selling vacant lot to a direct mailer - any red flags to look for

[Brian Henry]

We have a vacant lot in FL (Citrus Springs) and have been paying property tax for years, while the value of the land has decreased over the years.  We got a mailer offering to buy it and we are ready to just get rid of it.  Any red flags or things to consider before signing the offer and sending it back in?  They pay cash and cover closing fees.