You swear you're getting in shape in 2010. Your body. Your soul. Your skin? A mask could jump-start a healthy routine, say experts, giving a boost beyond daily washing and moisturizing (both of which you should already be doing).

The biggest investment in a mask isn't necessarily monetary -- although some can be quite pricey. It's really about taking the time to research the right one for your skin type and then executing it properly. Many people do masks only when they treat themselves to a spa facial because there's someone else selecting the product, and spa-goers are somewhat of a captive audience, says Peter Thomas Roth, founder and formulator of his eponymous skin-care line.

But, he adds, masks are easy enough to do at home with plenty of variety in the market and most don't take more than a few minutes. "Put it on before you before you brush your teeth, turn on the shower and by the time the water is warm, you can wash it off. You don't have to just sit there and watch the bubbles on your face."

A bubbly mask, Roth explains, is probably one that is refreshing to the skin and aims to tighten pores.

If you're looking to exfoliate, which should help with later steps to nourish skin, Manhattan dermatologist Dr. Amy Wechsler says the right mask will help remove the top, dead layer of cells and promote cell turnover, resulting in a smoother appearance.

For intense moisturizing, Paul Tchinnis, director of research and development at The Max Huber Research Labs used for La Mer products, recommends a product with sea algae, which has shown to provide both immediate and longer-term benefits.

By design, masks are more intensive treatments for occasional use and not part of a daily skin-care routine. Sometimes delivery is achieved through a thick-texture cream, serum or a moist clay-based or claylike product that will then dry on the skin.

"Masks prep you in a different way than a regular cream," notes Roth. "You can't leave on a mask: It's doing something but you don't want to do it for too long. If it's working, eventually it will be too harsh."

There's no better time than winter to try a treatment since skin -- facial skin, in particular -- takes a battering in the windier, drier atmosphere, says Tchinnis.

Some additional guidance:

* A sulphur or clay mask tends to be cooling, which can calm inflamed or acne-prone skin, and is supposed to draw out dirt, oil and impurities, according to Roth. It's a very traditional mask.

* Shea butter is a go-to ingredient for a rich, nourishing mask, says Cerina Silvestro, esthetician at La Prairie at The Ritz-Carlton Spa in New York. It replenishes lost moisture and reinforces the skin barrier to keep existing moisture in, she explains.

* A cucumber-based mask is user-friendly for almost everyone.

* Salicylic acid, which comes from tree bark, aids in resurfacing, reducing the appearance of lines.