Need some advice from anyone who can help, and maybe from our luthiers. I may have a chance to buy a used luthier guitar at a really good price, but the guy is a slob, and lives in a pigsty. I just know I would feel really queasy every time I picked up the guitar, and in the end I'm sure I would wind up never wanting to play it. If it was anything but a guitar, you would normally say "What the hell, I'll just scrub it to death," but obviously you can't do that to a guitar. I'm sure the outside would not present too much of a problem, though it would still have to be done – it's the inside that bothers me. God know what kind of dirt, grime, smells, or other unhealthy aspects might be lurking within, especially on unfinished wood, which could absorb odors, etc. in a way that the outside might not. Is there any way of really cleaning the inside extremely well without doing damage to the guitar? If so, how would I do it? And what are the possible pitfalls. And what about the outside. As a last resort, could a luthier do this for me, and if so, about how much would that cost. Obviously if the cost is too much my bargain goes down the drain, and I wouldn't bother buying it in the first place. Appreciate any help, advice, or general thoughts. Thanks.

Or am I being silly, and I shouldn't even worry about it?

Hola Prominent
I do not think you are being silly at all.
Who wants a disgusting guitar in their hands?
Here are a few ideas that might work.
Do you say in the USA Hoover of vacuum cleaner? I mean that machine you use at home to clean the floor and works by sucking the dust off the floor.
You can use one inside your guitar but the problem is that you have to be very careful to check the mess after to be sure that the machine did not collect any lose piece of wood.
Another way is to fill up the inside of your guitar with a cloth that is like thick rough knitter jumpers/sweaters/pullover. A smooth cloth is no good. You need the knitted. Then you softly move it around to pull off any mess in there. But dry not damp for obvious reasons.
Then also leave the guitar out of the case when possible so that it can breathe.
I hope it works ok.
Saludos

Tomás

Tomas makes some very good suggestions. I might suggest also a Swifter Duster for cleaning the dust and residue from the inside. If the residue is too heavy such as with nicotine tar, then a rag soaked in denatured alcohol will work, but care must be taken to avoid contact with the outside finish, especially if it is French polish. Also don't let your rag get to saturated and avoid glue joints. If it smells then place the guitar on its back in a safe place and put a small bowl with cypress oil in it inside and let it soak up the fumes for a few days. Careful not to spill any oil. You can put a rag over the sound hole to speed up the process. In severe cases I have used paint thinner on a rag to clean the inside, but I would not recommend this as it may leave petroleum residue in the wood and effect tone. Also contact with glue joints must be avoided. Only time I have used paint thinner was on severely unsanitary inexpensive guitars.

On the outside for a lacquer or varnish finish, I would have no problem using a rag dampened in mineral spirits to clean it, then use a high grade wood polish to shine it up again, but only if it is really filthy. Otherwise a damp rag to wipe it good and follow with a dry quality guitar polishing cloth.

Another tip for vacuuming is to get a computer vacuuming kit that has the small hose and brush. It is possible to maneuver it around much easier. Also for odors put a small dish of soda in the sound hole and leave over night with sound hole covered and then put in the cypress oil as mentioned above. A small cup about 2 inches diameter by 2 inches high would work well for both and easy to get in and out of sound hole without spilling.