Bicarb (bicarbonate of soda or baking soda) is great to add to your laundry powder to freshen up your washing and is economical way to bulk up your laundry powder, making your detergent last longer.
It's better to use a ‘wool wash’ detergent and not your general laundry detergent. Wool wash is often a liquid and will soften and condition the wool fibres for a longer life.
Resorts, and their high use towels, use special commercial softeners to get their results but here is some home, affordable tricks, to get a similar result. It’s all to do with Vinegar, dryers and woollen dryer balls.