Just the Goods products are made without the use of artificial preservatives. One of the easiest ways to do this is to blend/pack/ship products dry to avoid potential mould growth. Examples of dry facial care products are Just the Goods' petal, leaf, root. by Just the Goods cleansing grains, Just the Goods facial scrubs, and Just the Goods face masks, all of which are made from a variety of dried botanicals and mineral clays.
The easiest way to use cleansing grains and/or facial scrubs is to wet your face and your hands, shake a bit of product from the bottle or jar into the palm of one hand, then rub your palms together for a quick moment before transferring the product onto your face using gentle circular motions. Rinse well and follow with toner and moisturizer of your choice. Tips for how to use toner effectively can be found here: https://justthegoods.net/pages/tips-for-daily-skin-care
Another option is to handle the cleansing grains and/or facial scrubs like face mask by blending dry product with water prior to use. To do this, sprinkle a small amount of dry product into a mixing dish; mix with water (or any other liquid of your choice; ie. rose water), and apply to your face. You may use your fingers/hands, or apply with a clean paintbrush that is reserved for use with facial care products only. Cleansing grains and facial scrub should still be used with gentle circular motions. All three products -- cleansing grains, facial scrub, and face mask -- should be rinsed well with water, and followed with toner and moisturizer. These products are best applied at a sink rather than in the shower to avoid getting the remaining dry product wet/damp.
How often you use facial scrub is entirely up to you since only you will know how your skin responds to the product/formula you've selected. My general suggestion is to start once a week then increase or decrease depending on how your skin feels. Some people can use the variety for sensitive skin as often as daily (i.e. if they have very easily congested skin, or if they're on medication that causes extreme dryness and flaking). Some folks like to use the variety for most skin types every few days, more or less depending on issues like humidity, medications that impact skin, etc. Others might find once or twice a month is all they need. The best way to find out what works best for you is to experiment.
To preserve these products for as long as possible, avoid getting water/moisture/humidity into your remaining dry product as contact with water/steam may cause mould growth. This means one should avoid putting wet hands or spoons into a bottle or jar, avoid letting water drop into bottles/jars, and keep the product lids well sealed between uses. These products, like all other Just the Goods products, should be stored in a cool, dry place. Since many Just the Goods products are made from food grade ingredients (i.e. oat flour, amaranth flour, rice bran, etc) think of them like food and store them accordingly. In the same way that you wouldn't want to store an oatmeal cookie in the shower/allow them to get wet, please don't store Just the Goods products in a shower as doing so will render them spoiled and unsuitable for use.