I know time and time again, we each come up with an easy How-to or $$$ saving trick that would be good to share.  Add your ideas here.  If it will only work for a certain brand, or certain model, please specify.
 
Making plastic shine:  Pledge or any wax based furniture polish works well to keep your plastics looking shiny.  It's only a buck or two for the store brands and they work just as well.  Just spray on and wipe with a paper towel.  This is safe for decals.
 
Cleaning stickers off tunnel or plastic:  remove as much of the sticker as possible by pealing.   3m Adhesive remover.  Soak a paper towel or clean rag with it, wipe across adhesive area and the gunk will come right off.   Safe for plastics on Revs, I haven't tried others yet.
 

Better idea for stickers---- buy a heat gun

Ski Alignment.... any sled...
 
http://www.mainesledder.com/showthread.php?t=2112
 
 
Ski-Doo REV Chassis....
 
Poor man's clutch kit - Most all BRP's clutches are a tuned a tad lazy in stock form & begin the shift out too soon... cheap fix is a secondary spring with a higher "start rate".... low end & midrage acceleration will improve, as will backshift, without effecting top end at all.
 
If you have a 600 you likely have a "black" secondary spring... swap it for a BRP "green"
If you have an 800 you likely have a "green" secondary spring... swap it for a Dalton Ind. "red"
 
Gearing - Speaking of wasted acceleration, they're also "overgeared" from the factory... for reasons it would take too long to get into here... but you can go down one tooth on the top gear in your chaincase for improved acceleration without effecting the top end (your clutch will simply shift out further up top to compensate)... if you don't ride lakes or the county much at all, going down 2-teeth will pull like crazy off the line & out of the corners on the trail... the downside is this may cost you a few miles per tankfull.
 
Hanging Idle - If you have a carbed sled with that annoying "hanging idle", swap the stock #17.5 pilot jets for a pair of #20 & go 2 turns out on the fuel screw.
 
Belt Dust in Carbs/Throttle Bodies - You'll likely find fine particles of belt dust in your carb/throttle body inlets when you take 'em out for service... if this bugs you, remove the outer airbox & affix some prefilter material over the holes you'll find in the outer side of the airbox.
 
Summit Airbox - If you have a REV 800, the 07 Summit 800R Airbox has a larger opening between the halves and is good for a couple extra HP up top.
 
Lightweight Single-Ply XP Track on a REV - The new lightweight single ply XP 120" & 137" tracks can be used on a REV sled by changing to the 2.86" pitch drivers from the 06-07 440 race sled... then recal your speedometer for 9-tooth drivers.
 
A couple notes on swapping to the XP track... this also has the same effect as dropping 2-teeth on your top gear as the 2.86 8-tooth drivers are near the same diameter as the 2.52 9-tooth drivers, so you may want to change your gearing accordingly... also, for the Renegade, after the 1st season you may find you're running out of track tension adjustment as the track stretches, you'll need to pick up an offset axle & 8" wheels to compensate.