I have recently started getting into botany and have gotten a few house plants. I have been having problems with three of them; my Hoya, Bird's Nest and Ivy plants as the title says. It almost looks like something has been eating my Hoya and Bird's Nest plants. Although I have checked very carefully and can not see anything on them. There are pieces missing from a few of the leaves of my Bird's Nest and same with my Hoya. Also some of my Hoya's leaves are turning brown. Could this be from overwatering? I believe for a while I was overwatering them. Then there is the Ivy, which has small brown holes in some of the leaves.
Also is it natural for Hoya's to develop small grey spots on them? At first I thought this was from overwatering so I rubbed some vinegar on the leaves, which did nothing. Then I saw some pics of healthy flowering Hoya's online with the same type of spots on them. Thanks for any input, I'm a little worried and am especially attached to my Hoya. Also I'm not sure why I can't actually post my pics in this thread so here's a link. Thanks. http://postimg.org/gallery/2jysnyv6/9cfc9697/
...First three are the Ivy, next three the Hoya, last two Bird's Nest.