Hi,
I noticed that the bones work better for Jack than Ruby so I still continue to use the oral gel on Ruby.
Luckily, Ruby is co-operative and enjoys licking the gel but not Jack though!
It is likely to take some time before the tartar is soften to be removed.
Recently, I just use my finger nail to nick on Ruby's tartar to try to scrap it off.
I managed to get a reasonable chunk out from his incisor or front tooth.
Here is a photo of it so do be patient on the whole process.
But it is still a long way to go but it definitely works .......
David