The 6 Pocket-Square Commandments   Yes, pocket squares are all about feel and personal style, but there are still a few practical rules you need to know.  1. If you blow your nose in it, it belongs in the pocket of your pants, not your breast pocket. These are strictly for show.   2. Shiny silk pocket squares are out of style. (With apologies to all the dandies out there.)  3. You can spend $180 on cashmere that's shorn from the fleece of Italian unicorns, but you'll look just as good if you spend only $8.   4. Try wearing a square that echoes a color in your shirt or tie. If your plaid tie has a subtle red stripe in it, maybe go for a square that has red tipping.   5. If it makes your breast pocket bulge too much, you need to refold it or get a smaller square.  6. It's okay to spend two or three minutes in front of your mirror fiddling with your square until you're happy with it. Nonchalance takes practice.   Would you wear the same tie two days in a row? Think of these the same way: Build a stash that can get you through a workweek.  Clockwise from top left:   Ferrell Reed, $50   Tommy Hilfiger, $25   Sid Mashburn, $55   Hugh Crye, $20   Engineered Garments at Nepenthes, $43   Hav-A-Hank, $15   Mark McNairy, $18
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