Both stamps and cutters are best hand-washed in lukewarm water with an antibacterial soap. They can usually stand being put into a household diswasher, but as dishwasher settings and temperatures vary, you do so at your own risk.
Cutters are 3D printed in such a manner that will, under enough force, allow the layers to be separated. This shouldn’t be the case under normal use, but is something you should be aware of and does not usually constitute a fault with the product.
Stamps are made of acrylic, which is likely to break if dropped onto a hard floor (e.g. tiled). This is not considered a fault with the product as it should not be a problem with normal use.