Although not directly a care product, using a liner will mean your sleeping bag stays cleaner and reduces the need for washing the sleeping bag – both a time consuming and, in the long term, damaging process. Additionally, by using a sleeping bag liner you will prevent body oils and dirt from affecting the insulating properties of your bag and the liner itself will often add warmth of 1 or 2 degrees celsius to your sleeping bag. You can pay as little or as much as you want for a liner with prices starting at around the £9 mark and peaking at around £50+. Typically they are available in cotton or silk with cotton being the cheaper option while silk packs down far smaller and weighs far less – a consideration if you are backpacking. Silk and Thermolite liners can also add a lot more warmth than cotton liners. Furthermore, you can opt for rectangular or mummy shaped liners to match your sleeping bag shape. Liners also have another use as they can be used on their own in warmer and more humid climates as a sheet. This creates a barrier between you and the ground but wont make you too warm during the night.