Apparently, vinegar isn't, but onions and garlic are...
http://www.vetinfo.com/dtoxin.htmlIf you already treated with Frontline, no other poisons! They have the same toxins and combining both the Frontline with any other toxin remedy can be a dangerous overload. If you still have the Frontline package, make sure it isn't a rip off imitation. I just saw this on the news last night. The package looks almost identical to the real Frontline, but if you look at where it gives the address of the company it should say that it's made in France. The rip off ones discovered so far have an address listed on the package as being from Australia. The rip off ones are NOT Frontline products, they don't work or don't work very well at all, and there's no telling what kind of crap is in it. Apparently, someone has cleverly been copying the Frontline packaging and selling crap medication. Don't buy the products sold on discount websites especially wedsites based outside the US as these are the ones that are buying up the fake Frontline and selling it at or near market price. If you bought it at a reputable pet store or drugstore, I wouldn't worry about it if you don't have the packaging anymore to be able to check.
Keep the dog away from wooded areas, tall grass/weedy places and dead leaves on the ground until it gets cold enough outside to finally kill the buggers. Supposedly, it takes a couple of weeks of solid cold weather of below 40 degrees to kill them off and their eggs.
Treat your house. If there's so many that you find them on furniture they may have infested the house and laid eggs. Get some of those foggers to blow out the whole house and get rid of all the creepy crawlies. A bit of a pain in the ass, but if you're finding this many ticks and even on furniture, there's a really bad ass monster tick infestation somewhere that the dog is getting into.
Ticks seem to be a good deal more hardy than fleas and may still latch onto the treated dog and take a little longer to croke.
Always check with a vet or research reputable pet medical websites before dispensing home remedies so you don't inadvertently poison your pet.