Ok... I have tried a number of different off the shelf plastic spray bottles. They all seem to fail in fairly short order. Some will work again if you (yuck!) suck on the nozzle for a second. Its like they lose their prime and won't self prime again.
I have noticed that the pumps in the commercial products (rather than the bottles bought as generics) seem to hold up better. I've got an old Meguiers clean and shine product bottle that has had a dozen refills of misc gunk through it and it still works ok. Currently its filled with vinegar and water for removing hard water and river gunk from my boat when I bring it back from the river.
The thing is I would like to be able to find a source for spray / squirt bottles with pumps that will hold up. I need to spray various things from oil to WD to cleaner and none of the pumps seem to last. I bought a gallon of WD and a bottle with their label on it about a month ago, and already the pump is experiencing lost prime and won't pump back up without a little help. If I set it down for half an hour and pick it back up it will have lost its prime.
Gack.