Learn Hardcore Indonesian: Sebelum masuk, kami memakai pembersih tangan.

So use kami if you’re talking about your group and not the person you’re speaking to. If you mean to include the listener (e.g., a reminder to everyone present), use kita: Sebelum masuk, kita memakai pembersih tangan.

Do I need to repeat the subject after sebelum (e.g., sebelum kami masuk), or is sebelum masuk enough?

Both are correct.

Sebelum masuk, kami memakai… is fine and common when the subject of both clauses is the same.
Sebelum kami masuk, kami memakai… is explicit and slightly more formal. If the subject changes, you must state it: Sebelum dia masuk, kami memakai…

Is the comma after Sebelum masuk necessary?

When a time clause like sebelum… comes first, a comma is standard: Sebelum masuk, … If you move it to the end, you typically drop the comma: Kami memakai pembersih tangan sebelum masuk.

Do I need ke after masuk? When do I say masuk ke [place]?

Use masuk by itself when the destination is understood. If you name the destination, masuk ke [place] is very common: sebelum masuk ke toko/gedung. You’ll also hear set phrases without ke (e.g., masuk sekolah, masuk kelas)—both patterns occur in real usage.

What’s the difference between masuk and memasuki?

masuk is intransitive (“to enter/go in”), often used with ke: masuk ke gedung.
memasuki is transitive and takes a direct object: memasuki gedung. Meaning is similar; memasuki feels more formal: Sebelum memasuki gedung, …

Is memakai the right verb for hand sanitizer? Could I use menggunakan or mengoleskan?

All are possible, with nuances:

memakai = use/wear; very common and natural: memakai pembersih tangan.
menggunakan = use; a bit more formal but equally correct.
mengoleskan = to apply/spread (onto something), so it expects a target: mengoleskan pembersih tangan pada tangan. Use this if you want to highlight the act of applying.

Could memakai be misunderstood as “to wear” here?

No. memakai can mean “to use” or “to wear,” and context disambiguates. With pembersih tangan (a substance), it’s understood as “use/apply.” With clothing, it means “wear” (e.g., memakai jaket).

Why not say tangan kami (“our hands”)? Do body parts usually take a possessive?

Indonesian often omits possessors for body parts when it’s obvious from context. pembersih tangan already implies “hand sanitizer (for one’s hands).” You’d use tangan kami/ku/nya only if you need emphasis or contrast (e.g., not someone else’s hands). tangannya means “his/her/their hands” or “the hands (in a specific context).”

Is pembersih tangan the most natural way to say “hand sanitizer”?

Yes, it’s standard. Variants include cairan pembersih tangan and antiseptik tangan. The loanword hand sanitizer is also widely used on signs and packaging. Note: cuci tangan means “wash hands,” not “use sanitizer.”

How are pembersih and memakai formed morphologically?

pembersih = peN-
- bersih (“clean”) → a noun meaning “cleaner/cleansing agent.”
memakai = meN-
- pakai → the prefix assimilates and the initial p is dropped, yielding memakai. Both are very common derivations.

Does the sentence refer to past, present, or habitual action?

Indonesian doesn’t mark tense on the verb. Without time words, it can be present or habitual. Add adverbs for clarity:

Past: tadi/sudah (e.g., Sebelum masuk, kami sudah memakai…)
Progressive: sedang (rare here)
Future: akan (e.g., kami akan memakai…)
Habitual: selalu/sering

Can I move sebelum masuk to the end?

Yes. Kami memakai pembersih tangan sebelum masuk. Same meaning, no comma needed. Position it wherever it flows best.

Is it okay to leave masuk without saying where we’re entering?

Yes. If the place is understood from context (e.g., a store entrance), sebelum masuk is perfectly natural. If needed, add it: sebelum masuk ke toko/gedung/kantor.

How would I phrase this as a polite sign or instruction?

Use an impersonal imperative and drop the pronoun:

Sebelum masuk, harap gunakan pembersih tangan.
Mohon gunakan hand sanitizer sebelum masuk.

When would I use memakaikan?

memakaikan means “to put something on/apply something for someone else.” Use it when you do the action to another person: Saya memakaikan pembersih tangan pada anak.

Can I use dulu instead of sebelum?

dulu means “first/beforehand” (adverb), not the subordinator “before.” You can say: Kami pakai pembersih tangan dulu, baru masuk. It’s natural and conversational, but it’s not the same structure as Sebelum masuk, …