Ok, here we go: you have a piece of teak furniture and you have a hunch it could look a little nicer... you could:
1) leave it alone, let it turn grey, believe that it will be better "sun washed"
2) leave it alone, let it turn grey, wish that you had spent a little time restoring it
3) restore it before it totally turns grey and be gleeful that you did.
I picked 3...
5 Things To Note:
1) don't attempt to do this without a power sander
2) buy more sandpaper than you think you will need (ex - 4 sanding pads per chair)
3) the luster and depth of your teak furniture will astound you once you've spent a hard earned day renewing it
4) ... if only it was the teak on my boat I was working on... but then it would be my deck hand doing all the labor while I sun bathed...
5) treat yourself to a manicure after this is done <3
You're going to need a few things:
1) Teak Furniture - scored my 2 chair + cafe table set for $100 on Craigslist
2) A Power Sander - I borrowed my sister's Black and Decker Mouse Sander - she might not get it back.
3) 120 Grit Sanding Pads - see #2 above: you need more than you think + you will not want to have to stop sanding in between to run to the hardware store for more once you get started - the Diablo brand doesn't fit the Mouse perfectly and that doesn't matter either - just get lots of them
If your furniture has been really neglected you may want to get some lower grit sand pads to start with (the lower the "grit" the more coarse the sandpaper is) - 80 Grit Sanding Pads would be good to start with, then finish with the 120 before oiling.
4) Teak oil - self explanatory
5) Old T-shirt Rags - to wipe furniture off after sanding as well as to apply the oil
Other things you need but may not have to purchase:
1) An iPod loaded with your favorite Justin Timberlake tunes (I forgot this critical step)
2) Determination to continue sanding even after your fingers feel like tuning instruments
Here is what you need to do in alpha numerical order:
a) Load your electrical sander up with one of the many 80 or 120 Grit mouse sanding pads you purchased.
b) Start sanding (about an hour per chair, the table top took much longer as it had been exposed more to rain and sun) Remember to get all of the previous product off.
Each piece of wood that constructs a chair is called a "member" - each member has 4 sides, you do the math. It's a lot of sides + crevices you would not think of - sand them ALL - underside too.
You'll notice when you start to get under the outer oxidized layer of wood that a lighter pinkish wood will start to show through. This is what you should look for. Try and remove as much of the grey as possible. I would typically see the pink show through near the edges first then work towards the center of each slat.
c) Wipe down all sides with a cutoff t-shirt rag.
d) Shake the can of oil up and apply the first coat of oil to ALL surfaces of the chair using a cutoff t-shirt rag, you can't really mess up, just don't forget anywhere + you're fine. The fiery, inconsistent color of the wood will brighten and immediately look better.
e) Wait 30 minutes, let it "cure" (i.e. sink into the grain and begin to harden).
f) Re-apply another coat (don't forget this, it's like the top coat on your nails that prevents chipping).
g) Let cure for 7-10 hours for complete absorption + hardening.
h) No topcoat is needed - just some TLC in the form of an oil massage every once in awhile.
You will be so happy you took the time out to do this, your outdoor area will thank you. <3