According to the Oral History by Mr Mohd Amin, Toyol is kept as pets. They are obedient creatures that will follow any of its owner's instructions. Toyols are often used as a tool for people to get a quick buck. They are able to steal valuables from others without being detected, it is convenient 'pet' to own if you're in need of quick money.
The images here are evidences of people owning Toyol and keeping it in jars.
These Toyol can be easily distracted by marbles and toys as it is essentially a child and has short attention span. I was once told that olden people used to keep marbles and locks of hair inside their jewellery box to avoid them being stolen by the Toyol.
Apparently, the Toyol will forget about it's mission to steal your valuables and starts playing with the marbles and lock of hair until the sun comes up and it will return to its owner, failing its mission.