Tropheus can be safely stripped after 10 days IF an egg tumbler is used to properly agitate the eggs. If you are not going to use a tumbler,, you need to let them carry for 21 days at a minimum but an airstone with heavy aeration in a 2 gallon tank or less must be used to agitate the fry. This will preclude any deformities occurring.
To make them spit, wet your hand, firmly grasp the female over a small tank, bowl or pan filled with tank water, and with her submerged, hold her opercles shut while using a fingertip or fingernail to pry the lower jaw open very gently. The female will gasp and dispell some fry. Repeat this until all fry are spit out, it may take several attempts to get them all.
Difficult females may need to rest between attempts. Tropheus are pretty good mothers but most will release without too much trouble. You will have a few females that are very tenacious. You must decide if you will hurt her or not and if you wish her to carry full term and release in to the colony tank.
The biggest reason for having them spit is to get them reconditioned again for another spawn. Some females will eat while carrying, others will not. DO NOT take the female from the colony and have her recuperate in a separate tank. It will disrupt the colony heirarchy and she may be killed when returned. After stripping, return her to the colony immediately!
If you have any Metriclima zebra variants to practice on, they are easy to strip. Practice makes stripping less scary.
Remember though that if you feel that you will injure the fish, don't do it!