First of all, you should ALWAYS supervise your bird and what she's doing. Period. She can't be allowed to chew on furniture and such, no so-much because she's ruining things, but because she may start chewing on something that is toxic/poisonous to her, such as paint/stain/varnish on furniture, stain-proofing on carpeting, etc. It only takes a couple tiny flecks of toxic paint or wood stain to kill a little bird. So you need to make sure that when she is out of her cage flying around, you know where she is and what she is doing. And as Monica already stated, when you see her start to chew on anything that isn't her's, immediately give her something that is her's to chew on...
As far as her actually flying out of your house, i don't know how that's happening, as most bird-owners are not lucky enough to have that happen once and get their bird back, let alone twice...Three Strikes and You're Out is probably a safe-bet at this point, so please, try to figure out a system for not opening the doors to your house when she is out of her cage...Make signs that say "THE BIRD IS OUT OF HER CAGE" and stick them to every door to the outside when she is out free in the house, that way everyone inside the house will know not to just open the door, or even worse, to prop it open for some reason...That just can't keep happening, as I already said, you have no idea how extremely lucky you are...Take a look in the "Lost and Found" forum here and read the endless number of heartbreaking posts of members who accidentally let their bird's slip outside and have not ever seen them again...it's devastating.
***As far as clipping wings goes, we all here need to remember, before we post, that every single person has a different bird, in a different house, with different people in the house, all with different schedules and routines, etc. What is good for one person isn't necessarily good for someone else. What works for one person doesn't necessarily work for someone else. And clipping a bird's wings is a very personal decision for the bird's owner, and in my experience it's never an easy decision for the owner, such as in this post...if this was an easy decision for the OP they wouldn't have asked about it in the first place, they would have just clipped their bird's wings and that would have been it. So before being judgmental and just automatically telling the OP "Don't clip your bird's wings, it's not fair to the bird, they'll be much happier flighted, etc.", try to put yourselves in the OP's shoes. She's had her bird escape from her home twice, and been lucky enough to get her back both times...chances are she's not going to be so lucky a third time. And although "fixing the issue" as to how the bird is getting outside would be ideal, sometimes that isn't an option, sometimes the reason it's happening is unknown, etc. For one reason or another it keeps happening, and in the immediate, the most important thing is to keep the bird from being able to get out a third time...So maybe clipping the bird's wings and then using the couple of months that the bird can't fly to discover all of the issues and fix all of the problems is the safest solution for this OP.
The important things to know about clipping your bird's wings are that #1) Though it will most-likely cause your bird anxiety while it's being toweled and clipped, it doesn't actually cause the bird any pain at all, IF DONE PROPERLY AND CORRECTLY, #2) You must have her wings clipped by someone who knows what they are doing, either a Certified Avian Vet, a long-time bird Breeder, etc. so that your bird's wing feathers are not damaged in any permanent way, so that no blood-feathers are cut, and so that no pain is caused, #3) ONLY HAVE HER OUTER-MOST 3-4 PRIMARY FLIGHT FEATHERS ON EACH WING CLIPPED, any more is excessive, unnecessary, and can cause future issues, and #4) If the clip is done well and only the outer-most 3-4 primary flight feathers are clipped, your bird should grow her feathers back and be able to fly again in about 2 months or so...It's painless and it's temporary is done by a professional, so don't feel any guilt about those issues...
***The best advice that I can give you is to Please Utilize The Time While Your Bird's Wings Are Clipped To Train Your Bird And Make The Necessary Changes To Your Household!!! While I don't like to clip a bird's wings, I do feel that it is sometimes necessary, but only on a temporary basis. I do NOT think that a bird should be kept permanently clipped simply because it's owner doesn't want to be responsible for supervising their bird or making sure that proper procedures and routines are put into place in their home and with all of the people who live in the home in order to keep the bird safe and keep it from escaping to the outside. So please, if you do clip your bird's wings, utilize that 2 or so months while he cannot fly to make a plan for what you and the other people who live in your house will do after he can fly again...