Sure!

“I don’t care who they are, if I’m asked I’ll give grammar tips to whomever.”

Whomever is tough, because often this would be constructed as “I’ll give grammar tips to whoever asks.” And you would use “who” there, because “whoever” is the subject of the clause “whoever asks.”

Generally speaking, it’s usually safe to pick “whoever” over “whomever.”

But if you drop the “-ever” it’s a lot easier. Anywhere you’d use “him” (that is, the objective pronoun), you use “whom.” To whom, for whom, by whom, etc.