There 3 formulas for bleach soap caps for three different situations:
1.Light Stain Removal- 1oz.scalp bleach + 1oz. shampoo + 1oz.water, apply at the darkest part of dry hair, usually the bottom and work UP the shaft towards the scalp, do NOT apply mixture to scalp, the heat zone will make it come up way too fast, just before you take it off can you apply it there if and only if you need to.
2. Medium to Heavy Stain Removal-1oz.scalp bleach + 1oz.10vol or 20vol (depending on the amount of color to lift out) + 1oz. shampoo- apply this to dry hair until it starts to lift, again avoiding the scalp area until the last few minutes or avoiding entirely.
3. Heavy Color Removal- Scalp Bleach + water in equal parts.
Apply this to dry hair, again putting it on the darkest area first, which is usually the bottom.
In All of these situations, you can NEVER leave the client, as there is NOT any timing rule to follow on this, you'll need to watch and test the hair, every 5 minutes, remember to wet a towel and take off the bleach in an area to see if it's ready to be rinsed as most lighteners have a bluing or violet tone to them which you can't see thru.