I can buy it in sealed 24 x 500ml bottles and open a bottle then throw away what's left.
Sat here in the coffee shop searching info and hp is massively used in LM cleaning, why are they using hp? It is not the same as powders and I believe more active.
Using dyegone as an example, it works amazingly, I tried using the powder boosted with ammonia and there was no comparison.
I don't yet know what the difference is between liquid & powder but they are not the same, I think the liquid is not heavily sold because of the rate of decline in its performance.