Think of the surface of your logs like your skin and your stain like your sunscreen.  Now if you look at the pigments in your stain as the SPF of your sunscreen we get a better idea of the type of protection you are going to get out of your stain.  Now we know that the more SPF in our sun screen the more protection from the suns UV rays we have and the less we need to reapply.  
Now most of us love the NATURAL look, however those stains have very low pigments giving us an SPF rating of let's say 10-15. This means we don't get as much protection from the sun and to keep that natural look we have to do much more maintenance. Where as if we choose something with more pigment like a Bronze Pine or a Chestnut we get a higher SPF rating of let's say 45-60 and now we get much more protection and life out of our stain.


For this process we recommend you call in the professionals.  Glass blasting equipment can be rented but really would you take your brand new car and grab a guy off the street and say here sand and paint my car.  Yeah that is what I thought...send me an email and I'll give you some names of people who do this for a living.  As for Chemical washes and stain removers if you do not have a neutralizing agent they can remain on your logs and cause the new stain to fail.  If you are going to tackle this stage on your own do so with caution.  


Blasting can leave your logs pitted and rough so whats next?  This step can be done by you for sure so lets get to it you will need Orbital sander, and mouse sander, or a variable speed grinder. Now if you did not want to blast you can sand off old stain but of course this will take some time.  60-80 grit is the magic number it is a log home not a coffee table it is meant to be a little rough.