Now you may have drainfield pipe that cant handle a snake ( Old and brittle )  The caustic soda may help , but you have to get the liquid level down in the pipe .  

The windows on this house and on my residence nearby have brittle plastic inserts holding the glass on all four sides on the exterior.

But it depends on one tiny metal gear tooth per tumbler, so unless the gears are made of something insanely hard but not brittle, they can be broken with the force method.So everyone has heard the same stories and seen the same videos as me, but no one has actually heard of a burglar forcing one?

If they are very brittle they are getting old also.

Proud people are brittle.

They can barely afford to pay their mortgages and taxes there and live in perpetual fear that they'll have to downgrade or move their kids out of the school system they're in, an unthinkable loss of social status.As their kids grow, they unthinkingly strengthen then strong and weaken the weak, culminating in too many avoidable instances of weak, brittle, fearful young people of privilege who are unable to deal with any sort of real adversity and only really do anything when faced with the possibility that inaction might significantly damage their own precious social status, documented daily on Instagram, Facebook, etc.So in my private life of old friends and family, I find myself somewhat hemmed in by incredibly hard-working people who care a great deal about social status and constantly make utterly inane excuses about why they're all so damned broke as they drive massively depreciating cars and live in houses that are dumpster fires of various expenses.

It's brittle, and it breaks.

It gets brittle and cracks after a few years.

It will be way too brittle and cost more in the long run. 

i stopped using plumbers putty years ago. it cracks just about a year later and becomes brittle. now, i just use the GE silicone or whatever the 7 year one is. no more issues.