Do you send a NON guarantee with estimate

[leofry@1966]

I am sure this will have a lot of controversy, but have you ever been asked to give a estimate on a carpet or tile and grout that has never been cleaned in like say 20 years... even though i tell them hey this has not been cleaned in such a long time i really don;t know what it will do and EVEN with a demo just because that spot come clean does not mean a area in front of the door or the bathroom stall will come as clean ... so i get if its a $100 job maybe you eat it if that is what you want to do but what if you clean a huge restroom and you are getting up all kinds of dirt but there are some areas that did not do well.

A. Do you cover this in the estimate saying you can't guarantee
B. keep cleaning it like 5 times turning a 8 hour job at $100 an hour to a 30 hour job turing it in to a $26 an hour job
C. eat it say your sorry don;t pay
D. just tell them its to far gone, althogh i have seen some dramatic results but i have also not seen then

contrary to what some may say here or on other post somethings can not be restored