Masks - Clay/Mud/Charcoal etc

Clay masks - the easiest way to give your skin a deeper clean without being harsh or spending a fortune. The market is FULL of them but as I have said previously (on numerous occasions), if you are on a tight budget, this is where you can save money.

Cattier are a French brand that make really affordable and really good clay masks - which is great if you live in France but not so great if you don't. They're available in every pharmacy and literally cost a few euros. You can buy them in pink, white, green and yellow clay, and you can buy them ready-made or as a base powder clay that you just add your chosen liquid to. Simple.

In the mid-ranged pricing arena you can find Clarins Pure and Radiant Mask which has been a bestseller for years - and with good reason. Easy to use, light, not too much tingle, and leaves the skin soft, not dried out. Excellent.
Origins Clear Improvement has more 'oompf' and is perhaps better for an oilier skin. Another good choice, particularly if you're oilier.
Pixi's Glow Mud Mask is another easy option for all skin types and is in an aloe vera base making it softer than some, while still having a deep cleansing effect.

If you just love products and don't mind being a little more spendy, there are endless options. Peter Thomas Roth Irish Moor Mud Mask is mud, volcanic ash, seaweed and charcoal and works a treat. It's not so good with anything other than a really dark facecloth though - be warned. This is proper, black, goop - 'scaring the kids' territory.

The luxury end, unsurprisingly, makes beautiful products that do the job but are also a pleasure to use. Omorovicza Deep Cleansing Mask contains pure Hungarian Black Moor Mud that is loaded with calcium and magnesium that very gently cleans the pores with no tightness or drying. Skin is soft and clean afterwards.

May Lindstrom's The Problem Solver is based with Fuller's Earth, a stronger clay, and Red Moroccan Rhassoul Clay and comes in its original powder form, to which you add equal parts liquid, make a mousse and apply, ideally leaving it on for 45 minutes or until its dry. Brilliant.

If you fancy being a bit of a kitchen sink chemist, you could also buy yourself some powdered clay in its most basic form and make your own. It's what beauty students have been doing all over the globe for years. Not as easy as squeezing a tube or opening a ready made pot, but always an option. In the UK, Baldwins have been supplying clay powders to the industry for years, and you should find similar stores local to you wherever you live with a simple google search.

Masks mentioned:
Cattier - I'm not linking to Cattier's website because I think it's corrupted. My screen started opening all sorts of games/spam when I clicked on it - just keep your eyes open in case!
Clarins Pure and Radiant Mask
Origins Clear Improvement
Pixi Glow Mud Mask
Peter Thomas Roth Irish Moor Mud
Omorovicza Deep Cleansing Mask
May Lindstrom The Problem Solver
G Baldwin & Co

Happy to answer specific other brand questions in the comments. :)

MASKS - An Overview

There are literally thousands of masks on the market. Endless options for all skin types and all skin conditions. So where to begin?

Masks were traditionally a quick fix or an extra boost, normally used once a week to help possibly fix whatever issue you had.
These days they're much more sophisticated and can be left on overnight, used as a 15 minute quick fix, or used under moisturisers during the day if you so desire.

So what type of mask works best for which skin? More in-depth reviews will follow but for now the briefest of overviews:

Clay
The original and most well-known type of mask, clay is traditionally used for deep cleaning, decongesting, in general it's the one you grab when you feel a bit dirty, like you need a really good clean.
Best for:
oily, combination, blackheads, breakouts, dull
Avoid if:
Check the ingredients for magnesium and avoid if you're sensitive - it can be very stimulating.

Exfoliating
These are either bead-based (I don't recommend microbead masks, I'm talking about silica/jojoba etc), enzyme or acid-based and are used to resurface the skin, slough off dead skin cells, turnover the stratum corneum (15-20 layers of dead, flattened, skin cells) a little quicker to give you smooth skin.
Best for:
dull, flaky, sallow, dry, dehydrated
Avoid if:
sensitive, easily reactive

Moisturising
Moisturising masks are usually used last and add oil-based moisture to the skin. They're the perfect mask to sleep in if you're older and contain things like shea butter and oils.
Best for:
older, premature ageing, mature, dry,
Avoid if:
oily, combination, acne-prone

Anti-ageing
This is more a sub-category but worth a mention as a lot of the hydrating/moisturising masks use 'anti-ageing' as their main focus. These will contain peptides and other trademark name ingredients, some of which you will never have heard of, some of which you will.
Best for:
older, mature skins, skins worried about signs of ageing
Avoid if:
You're 21 (under 30) and just want a quick clay mask. Save your pennies.

Hydrating

These are generally water, glycerin and hyaluronic acid based, amongst others. They work great as a quick boost for all skins but work especially well for:

dehydrated, dry, dull, - basically a one-size fits all mask

Avoid if:

literally anyone can use these masks - when in doubt, buy hydrating

Sheet Masks
Ah sheet masks. Or as you may have come to think of them: bandwagon masks (maybe that's just me). Not since the dawn of face wipes has a trend hit so quickly, and so hard. Everyone is doing a sheet mask. These gained their popularity in the Far East and show no signs of going away.
Best for:
forcing you to sit still/lie down for a while - and the benefits of the ingredients obviously..
Avoid if:
You're very sensitive. Or at least check the ingredients as sheet masks can be heavy on fragrance and alcohol. Not all, but quite a few.